By April 1942, Klein was composing once again, and was busier than ever. He had a steady stream of new compositions, was preparing for, and performing in, concerts and rehearsals, and had his general responsibilities in the Free Time Administration. In addition, he was involved in the Youth Care Department, and was taking part in an ambitious lecture series. The main office of the Free Time Administration was in the Magdeburg Barracks (now part of the Terezín Memorial Museum and its archives) and so, in addition to his other workplace, L417, the Magdeburg is where he spent much of his time. Irma Semecká worked in the office and, in the final months of his imprisonment, they became very close, eventually falling deeply in love. Klein's senior by three years, she was enormously intelligent in her own right. She confided, in a letter to Lisa dated 3 June 1945, that ‘in those six months we did not say a single bad word to each other’. He used to visit the office ‘to warm up when his fingers were nearly freezing to the keys of the piano’, Irma recalled:

The studio, as Klein proudly called it, was in reality ‘a dark squalid cubbyhole with a window and bars, an old mattress replacing the window glass’, Irma said. She continues:

Klein's fellow pianist and friend from Prague, Truda Solarová, has presented a vivid picture of some of his work:

The war had given the Silesian coal mines a new lease of life, as old seams once considered unsafe could now be worked by a ready supply of slaves, who could easily be replaced if killed or injured by pit collapses. IG Farben, the German pharmaceutical and chemical company, which was also partly involved in the manufacture of the Zyklon B gas-crystals used in the gas chambers, owned a majority stake in the mines. A major Third Reich contractor, IG Farben considered health and safety to be an irrelevance; at any cost, the coal was required to make synthetic rubber for the war effort. Adjacent to the mines, the Fürstengrube site comprised a series of smaller camps, all within a short distance of one another. Lager Süd (Southern Camp), run by the SS, was the only one for Jews, and held around 1,200 prisoners by the summer of 1943. Lager Waldek held non-Jewish prisoners of various nationalities, Lager Ostland was for female prisoners and Lager Nord for Russian POWs. Although all the camps came under jurisdiction of IG Farben, Lager Süd was the only section affiliated to Auschwitz. The prisoners were tasked to work the old mine (Altanlage) and excavate a new one (Neuanlage); in both cases, the working environment was appalling. Having been in Auschwitz for only a short time, Klein would not have had time to discover that living conditions in Lager Süd were every bit as harsh as the main Auschwitz camp. Coming from Terezín, where, despite the squalor, he at least lodged with members of his own family, and had some relative freedom, his new environment, with prisoners packed like proverbial sardines, and meagre food rations, was a living hell. Moreover, the camp contained what were known as Muselmänner, a slang word originating in Auschwitz, derived from ‘Muslim’, to denote prisoners who were exhausted, emaciated and ill: Muselmänner had difficulty standing upright, and so the image of a prone Muslim at prayer gave rise to the expression. The hard labour of twelve-hour shifts inflicted on the prisoners was not supported by adequate food, and anyone on a late shift would find their rations back at the camp to be cold, or having been bartered by other prisoners.

By the time Klein was composing the last of his Prague works, the occupied city retained but a shadow of its former splendour. There had been a large influx of Germans, street signs and many newspapers were now in German, shops were becoming depleted of goods and the Czech currency had become devalued. For Jews, their wages had been capped and, in any case, they found it almost impossible to find work, as self-employment for them was prohibited. In November 1940 Jews were instructed to hand over their bank-account passbooks and so, in order to try and recoup some cash, they began to rent out rooms in their homes. In a city where Jewish poverty was previously almost unknown, they were now eating charity food in soup kitchens, as more and more restrictions were placed on them. All this hardship was in addition to the prohibitions inflicted by the Nuremberg Laws.

By September 1941 Jews had to register officially with the authorities so that the occupying Germans could monitor Jewish demographics. Jews had fallen so low on the social ladder that when, shortly afterwards, the Germans announced the establishment of a so-called autonomous Jewish town at the former army garrison of Terezín, it seemed an attractive proposition. Zdenka Fantlová explained: ‘We got out a map to see in what direction Terezín lay from Prague. It didn't seem so horrible. If they evacuate us to that place, we pondered, we shall still be on Czechoslovak territory, still more or less home-based – just elsewhere, in a different town’. The historian Margalit Shlain has written:

His formal education now over, despite clandestine tutelage from Hába and Hutter, and with basic freedoms for Jews being rapidly curtailed, Klein was nonetheless engaged in a hectic amount of musical activity. Though no longer performing in public as a soloist, he undertook regular work in the theatre playing for E. F. Burian's D-34 Theatre, which despite its characteristically leftist, though not overtly anti-occupation leanings, continued to function until Burian's arrest in 1941.

He also played for the avant-garde Divadlo pro 99 (D99 Theatre) at the Topičův (Topic) salon, near the National Theatre, established in January 1940 by Gustav Schorsch (1918-45), who was also its director. Only two years Klein's senior, a graduate of the Prague Conservatoire drama department, and a student of aesthetics and philosophy at Charles University, Schorsch was a remarkable person whose life hereon was to become intertwined with Klein’s. Schorsch's brilliant intellect and his phenomenal talent as an actor and theatrical director would ensure that he and Klein had much in common. For the same reasons that Klein, prevented from performing, turned more to composition, so too did Schorsch turn to directing from acting.

How these theatres could operate in practical terms under the occupation was testing in its own right. With so much Jewish involvement, maintaining a semblance of normality within the performing arts in Prague was a challenge, as the Jews’ basic freedoms were eroded. To say that Prague's Jews became imprisoned in their own city is no exaggeration, and this incarceration became increasingly severe. By early 1940, there was an 8 p.m. curfew for Jews, who were banned from theatres, cinemas and various other public places, and were permitted in restaurants only if rooms were set aside specifically for them. Before long, they were forbidden from owning radios, even from keeping pets, and so normal, everyday life and the ability to interact routinely with society became impossible. It followed that for non-Jews helping Jews to circumvent the prohibitions, the punishments were severe. Many non-Jewish Czechs nonetheless continued to help their Jewish friends and neighbours in numerous ways, while just as many took the decision to look out only for themselves and their families, and obliterated years of friendship in one fell swoop.

In 1943, the actress Zdenka Fantlová was playing the part of Aphrodite in a cabaret, Rabbi Akiba was no Liar – or was he?, written by Josef Lustig and Jiří Spitz. After one of the performances in the attic theatre of the Dresden Barracks, she had her only personal encounter with Klein, a chance meeting:

Whether playing to a single person, to a larger audience, or the ‘inner circle’, as Jan Fischer described it, Klein's recital performances in Terezín maintained the standard of excellence and virtuosity that he had established in Prague. There were any number of pianists in the ghetto, and once concerts became sanctioned and well established, venues were set up, confiscated pianos from Prague began to arrive and practice rosters were prepared for the players. Norbert Fryd recalls:

On 30 September, Karel Ančerl conducted his last concert in Terezín before being transported, along with Gideon Klein and many of the other musicians, to Auschwitz two weeks later. The concert consisted of Haas’ Study for Strings, which Klein had conducted in rehearsal, Dvořák's Serenade for Strings and Suk's Meditation on the Saint Wenceslas Hymn. This latter work, though dating from 1914, had become something of an unofficial national anthem, an intense nationalist elegy, for the Czechs. Undoubtedly, Klein would have been at this concert, and it is quite probably the last live concert music he ever heard. His dark mood in those final weeks in the ghetto are clearly described by Irma Semecká. When they went for a walk one day, he expressed his anxieties. Clearly he had not been taken in by the deception of the beautification, because he knew that the Terezín ghetto, from its very inception, was one huge, obscene sham.

The spacious house on Velké Novosady opposite the Evangelical Church of the Czech Brethren on what is now Drahlovského Street, no longer exists, having long since been demolished as part of a redevelopment scheme. But in Klein's day he enjoyed the extensive grounds and outbuildings, the physical backdrop for his cosseted, loving, cultured and, in many ways, exciting environment. Yet his encounter with music was not restricted to within his own family. By the early twentieth century, Přerov, with its agricultural industry amid the rich, fertile plains of Moravia, and also an important railway junction, was no backwater in terms of wealth or culture. During Klein's formative years it enjoyed high-quality music-making. It was close enough to the city of Olomouc for visiting professional musicians or actors to travel the fifteen miles from there every Monday evening to perform in Přerov's splendid neo-Renaissance Municipal House, putting on plays, concerts and even opera. World-class musicians, not least Leoš Janáček himself, were only 50 miles away in the Moravian capital of Brno. Eminent musicians regularly appeared in Přerov, including Dvořák's pupil, and at one time the principal conductor of the Czech Philharmonic, Oscar Nedbal, who on an unrecorded date conducted Smetana's opera The Kiss in the Municipal House there. Later to become a leading Czech theatre conductor, Zdeněk Chalabala gave orchestral concerts in Přerov. Emmy Destinn, one of the foremost sopranos of her age, sang in Smetana's Dalibor in Přerov, and the singer Magda Šantruček, one of Dvořák's daughters, lived in the town, where she organised concerts. Her mother, Dvořák's widow Anna Dvořáková, visited Přerov each year, as did her son-in-law, the composer Josef Suk, one of the major Czech composers of the post-Dvořák period. The town was a supportive environment for emerging musicians. Two of Klein's Přerov-born contemporaries would later become professional musicians: the conductor Vilém Tauský, and the violinist, composer, writer and illustrater Josef Kainar who was at school with Klein, the two of them performing together in a school concert in March 1931.

Klein spent his final winter, after he turned 25 on 6 December, in the freezing cold of Poland. As icy winds blew in from the north, he found an opportunity, remarkably, to smuggle out a letter to Prague. The details of exactly how that was achieved are still a mystery, but he was assisted by a prisoner in nearby Lager Waldek, Simon Pastre, whom he may have encountered on work duty. Any other contact between prisoners of the separate camps was impossible, and the prisoners sent from Auschwitz were deliberately and specifically isolated. Some prisoners, though not the Jewish ones in Larger Süd, were responsible for the mail service to and from to the camp, and it is possible that Pastre was involved in this activity in some way. Apart from the Soviet and Jewish prisoners, the ones from other nationalities were permitted to correspond with family, subject to censorship. There was always a risk of being caught for smuggling letters, the punishment being fifteen lashes in public in order to intimidate the other prisoners. But both Klein and Pastre must have felt it was worth the risk, so that the letter could somehow circumvent censorship; and it was, because it contains first-hand information about the dire circumstances of the prisoners which would have normally been expurgated.

The double-sided letter in Klein's hand is largely legible, and signed by him, though the name and address of the sender is that of Pastre, written in the latter's somewhat calligraphic handwriting. It would have been impossible for Klein to receive a reply, but more of a chance for Pastre to do so. Certainly, as the name suggests, and the fact that he had written the French word for address, ‘adresse’, Pastre seems to have been French, but beyond that, his identity remains an enigma. An inventory of the number of prisoners for that winter indicates that Waldek had among its prisoners 91 French, though no Belgians. One wonders whether Simon Pastre might have been connected with the non-Jewish Comtesse Lily Pastre, who helped shelter Jewish musicians in occupied France, as well as helping to preserve the music of Jewish composers by organising clandestine concerts. Conversely, this generous individual might have been using a pseudonym. Knowing that he no longer had family back in Prague, Klein addresses his letter to his sister Edith's mother-in-law, Marie Doláková.

The orphanage on Belgická was quite possibly where Klein first met Frantiská Edelsteinová (1917–44). She had been an outstanding medical student at Charles University, and lived a few doors down from the orphanage on Belgická. Almost three years older than Klein, she was mature, highly intelligent and a spirited redhead. In the winter of 1940–41, Gideon and Frantiská began a relationship, but after six months it was floundering, with Frantiská clearly frustrated that he would not, or could not, commit to the relationship as deeply as she would have liked. Things came to a head in the spring of 1941 and at the beginning of May she wrote a long letter to Klein, something of a cri de coeur, which reveals much about how he engaged with non-familial relationships, but also shows the intense love which Frantiská felt for him.

Dated 5 May 1941, she begins her letter ‘Angel – I decided to get down to it after all. That is to briefly summarise my half-year knowledge of you’. She describes Klein as ‘an intellectual type who has to a great extent broken away from the material world, from its practical and everyday side that is, and he is at home mainly in the spiritual world’. Yet she points to an apparent paradox by saying:

She then writes about his ‘inability or unsuccessful attempts at creating close relationships’, adding, ‘You are sometimes so uncertain when it comes to women, to whom you attribute certain assumed qualities’. Interestingly, this observation is borne out by Hana Žantovská, who, in 1946, reflected on her friendship with Klein:

At that time, Klein had a busy social life and the cafés, of course, often served as a backdrop to this activity. In such surroundings, he was no longer a mere observer, tagging along with Lisa to meet her friends. Café Mánes continued to be a favourite, but now that he was older, he would also frequent the students’ café on Na Zderaz, close to his old school. It was in 1938, at about the time of his school graduation ball, that he first met Hana Žantovská (1921–2004), who later became a noted Czech translator. They became close friends, though the relationship was not a romantic one. Hana first met Klein, ‘a very handsome young man’, as she describes him, at one of the cafés, and offers a very finely drawn portrait:

Through Hana, Klein met many of the young writers with whom she mixed, including the most famous of that young group, Jiří Orten, whose tragic death was to be immutably bound up with the fate of the Kleins during the war. Klein's knowledge of literature struck Hana immediately, observing that his understanding of it seemed to equal his expertise in music, that his friendliness and ability to connect with people was so evident, and that, in her words, ‘he knew how to share’.

I had a most extraordinary encounter with Gideon Klein. In one of the barrack-theatres in Terezín, Gideon and I found ourselves alone there, and as I was about to leave so that he could practise the piano, he invited me to stay. There, in that strange environment of the camp, this exceptionally talented young musician performed Chopin, just for me. In this book, you will read about this impromptu private recital, and the memory of that event remains as clear to me today as it was almost 80 years ago. As an actress taking part in many activities in the camp, I became acquainted with numerous prisoners who were central to Terezín's cultural life. From Gideon's friend, the theatre director Gustav Schorsch, who, you will read, was murdered alongside Gideon in Fürstengrube, to the pianist Alice Herz-Sommer with whom I met weekly in London up until her death in 2014, via the many others who make appearances in this book. All of them ensured that, despite appalling circumstances, the arts flourished during imprisonment.

I was also fortunate enough to know Gideon's sister, Lisa Kleinová, who, as the book details, played such an important part in her brother's life. Lisa and I were in Auschwitz-Birkenau together, and we were on the same death-march from that place. I was eventually liberated at Bergen-Belsen, and Lisa, miraculously, managed to find her way back to Prague. We kept in touch with one another until her death in 1999.

This book is the first full-length biography of Gideon Klein in a quarter of a century. Not only does it document Gideon's activities in Terezín, but it is the first piece of scholarship to detail his life, and that of his family, in Prague and Přerov. It is a fitting tribute, and an appropriate homage, to a lovely person, and a wonderful musician who undoubtedly would have become renowned, if a cruel regime had not ended his life so pitifully early.

In view of Klein's intense closeness to his family, the first few months in Terezín without his mother and sister must often have been distressing. Pre-printed postcards did occasionally reach Prague from Terezín, and Czech gendarmes could be bribed to deliver messages back and forth, though these channels carried huge risks. In short, whether he was able to keep in touch with his family is unknown. But on 20 July 1942 Ilona and Lisa arrived in the camp on Transport AAS from Prague. The period leading up to their departure was tense. ‘In that time, I was desperately looking for a lawyer for my brother-in-law who was sentenced to death’, Lisa recalled. In fact, for a short while before his execution in Munich in August 1943, Jaroslav Dolak was imprisoned at Terezín, in the Gestapo prison, known as the Mala Pevnost (‘Small Fortress’), across the river from the main ghetto. Lisa explained that she and Ilona prepared to leave their home:

Klein's aunt Reginka arrived a few days after Ilona and Lisa. Other members of the family were in Terezín, too, if only briefly, en route to their deaths. The Kulkas from České Budějovice arrived for a few days in April 1942, before being deported to the Izbica ghetto. Aunt Eliška, uncle Vítězslav and their daughters Hanna and Zuzana died in Izbica, and Hary and Arnost were murdered in Majdanek later that year. Additional relatives made brief appearances. Klein's aunt and uncle, Julius and Anna Marmorstein, along with their children Karel and Milan, arrived in Terezín towards the end of June 1942, but by the middle of July had been murdered in the Maly Trostenets extermination camp, south-west of Minsk. Aunt Isabela, whom Lisa remembered with such fondness from the Přerov days, was also in the ghetto. Isabela's sister, Paula Schenk, and her husband, Jindřich, arrived on the same transport as Julius and Anna, but were then transported to their deaths in Treblinka in October.

Initially proscribed by the Nazis, clandestine cultural activities started to take place in early December, largely to relieve the tedium and poverty in which the first inmates found themselves, but also as a direct result of the first executions. Nine men from Klein's AK group were caught for the ‘offence’, punishable by death, of smoking or of smuggling out letters to their loved ones. The writer Mirko Tuma, imprisoned in the ghetto from its early days, explains the connection between the first cultural activities and the arrests:

Klein's friends and fellow musicians, among them the pianist and conductor Rafael Schächter and the violinists Karel Fröhlich and Heini Taussig, as well as other musicians and actors, were there with him from the start. There is no evidence that he contributed to any of the early informal concerts which took place in the barracks in those first few days and, as a piano was not yet available for the prisoners, it is unlikely that he did. But some of the other musicians brought their instruments with them, although strictly it was not permitted.3 Even so, by the end of December, the Council of Elders reached an agreement with their captors, and the Nazi authorities sanctioned what were known as Kammeradschaftsabende (Fellowship Evenings).

Klein's experience as a performer increased throughout the 1930s. Nor was he idle as a composer. An encounter with a leading contemporary composer, then visiting Prague, inspired him to complete one of his first compositions extant from that decade. In 1933, Darius Milhaud, a member of the so-called Les Six group of French composers, visited Prague at the invitation of the ISCM (International Society for Contemporary Music), still today the foremost international forum for the promotion of new music; its Czech chapter was then especially active. Klein's Little Suite for piano, dated 27 April 1933, is his only surviving composition since the Suite lyrique of almost four years earlier – at least, there is no evidence to suggest that he composed anything between 1929 and 1933; his intense piano studies might have been the reason for his compositional silence.

The Little Suite comprises two short movements, an Andante followed by a Vivace, with an inscription at the end, ‘After Milhaud's concert’. In all likelihood, judging from the notation of the first movement in particular, and the single date it bears, the piece was written quickly, in a flash of Milhaud-inspired creativity. In the first movement, Klein is clearly experimenting with the type of jazz-influenced harmony that Milhaud uses. The second movement is a rapid nine bars, which tries to capture the velocity and unbounded energy of pieces such as Milhaud's 1923 jazz-like ballet score La Création du monde (‘The Creation of the World’), or his earlier ballet Le boeuf sur le toit (‘The Ox on the Roof ’). Although there seems to be no record of what he might have heard at that 1933 concert, this modern, Gallic style was something which clearly impressed him, and was championed by sections of the Czech avant-garde generally.

Apart from attending classes in general musicianship as a part-time student at the Conservatoire, Klein was not receiving any formal composition tuition at this time, and would not do so until his studies with Alois Hába began in 1939. Consequently, a work such as the Little Suite, not especially remarkable apart from the age of its creator, is unencumbered by compositional theory.

We are back in Prague, Klein's city. Many years have passed since the end of the Second World War. A short metro journey from the city centre to Želivského will take you directly opposite the New Jewish Cemetery. The information office will provide you with a plan of the cemetery and direct you to Lisa's plot. It is at the far-eastern end of the massive site. Walk down the right-hand path, closest to the perimeter wall, towards the well-visited grave of Franz Kafka. On the wall on your right, you will soon find Gideon Klein's name included in the memorials to those Czech artists slaughtered in the Holocaust. In the northern hinterland of the cemetery, you will find he is also memorialised on the reverse of his grandmother Kateřina's gravestone. In 2011, on my own intervention, Stolpersteine (stumbling stones) for Klein and his mother were placed outside the Rašínovo apartment in Prague: brass plaques, now widespread in what was Nazi-occupied Europe, are set into the pavement outside the last residential addresses of Holocaust victims, in memory of those who never returned.

Prague now enjoys a vibrant Jewish life, a revival which has gone from strength to strength since the Velvet Revolution. The Jewish Quarter is not only one large museum in its own right but also boasts active synagogues, kosher restaurants and an energetic Jewish lifestyle. But take time out, when there, to make your way to the Pinkus Synagogue. As you enter, and as your eyes adjust to the muted light, you will notice busy patterns on the walls. As you look more closely, you will find that these are the names of the Czech Jews who were murdered by Hitler's followers. Close on 80,000 names, handwritten. Find the northern wall, close to the Holy Ark, and look up. There you will find Gideon Klein's name. And somewhere, there is Ilona, and Aunt Reginka, and Edith, and Arnost. And you can find Rafael Schächter, Viktor Ullmann, Hans Krása and Pavel Haas, along with Gustav, and Gonda, and Jakob, and of course Frantiská. And far, far too many other names from this story.

Then leave the synagogue, and walk through the enchanting Prague streets, and remember what Hana Žantovská said about Gideon's love of ‘the Vltava bridges and riverbanks, books of poetry, small coffee shops’.

On his return from Italy, Klein would soon have reinstated his strict regime of piano practice. He also composed. He made some short sketches, dated 22 September, for a chamber work for piano and brass, possibly inspired by Janáček's Capriccio for piano and small ensemble, a work with which he was familiar. That same month, he completed his most ambitious work to date, the Four Movements for String Quartet, dedicated to Lisa, a piece he had been working on since the summer of 1936. Indeed, her brother acknowledges the slow gestation of the Four Movements when, at the end of the manuscript, he writes, ‘Completed after two years of work on the first of June 1938’, even though the revised fair copy was not signed off until the September date. The sketch for the second movement originally included a part for voice. Though this idea was dropped after a few bars, it shows that he was still interested in this combination, recalling his earlier sketches of a quartet with solo voice.

Considering that its composer was only sixteen when he began this piece, it is remarkable in a number of ways. First, its four movements last barely fifteen minutes, and yet are concentrated in concept, exploring his characteristic compositional pre-occupation with intricate, modernistic polyphony. Second, his acknowledgement of a contrapuntal style is stated outright, as the first four notes in the solo viola spell out BACH, a formula employed by Bach himself and many others, and in other drafts of incomplete works by Klein himself. These notes, normally adjacent, are displaced, so that he achieves his now distinctive angularity of melodic shape. It is unknown whether he felt that his compositional style lacked the profound logic one usually associates with the title of ‘string quartet’, or that the genre was too encumbered with historical baggage. Certainly, he does not adhere to the closed forms of the Classical string quartet, and yet by the 1930s the string quartet had evolved into one which was no longer hampered by convention. In the event, Klein's work does demonstrate stylistic cohesion, in music which is influenced by both the Second Viennese School and Janáček.