The work behind this book began more than 25 years ago when we, the authors, were young history students at Roskilde University in Denmark. During our studies we came across the fact that thousands of Danes (how many was unknown at the time) had joined the Waffen-SS and chosen to fight for Hitler during the second world war. Yet no one had examined the history of these men whose actions so obviously ran counter to the many stories of resistance fighters and the rescue of the Danish Jews that we had been brought up with. In contrast, the academic, and indeed the national, interest in those who had chosen the wrong side was almost non-existing. This caught our common interest to a great degree and we chose to study this phenomenon.

Starting out as students we spend four very exiting years interviewing former SS-soldiers, and digging through archives in Germany, the Czech Republic, Russia, Sweden and Denmark in an attempt to locate the Danish volunteers in the vast machinery of the Third Reich. It was sometimes like looking for a needle in a haystack and with little money in our student pockets we spend many nights at youth hostels around Europe while researching huge amounts of Nazi records in different archives during the day. Remembering those days together now, when finishing this book, makes us smile as we think back on the immense amounts of time and energy that we were able to dedicate to our academic endeavours in that early phase of our lives. In 1998, we published a book on the Danish volunteers in the Waffen-SS for the first time documenting, among other things, how these Danes had committed war crimes and in various ways contributed to the Nazi war of extermination.

We also realised from the start that the Waffen-SS was an organization that could tell us something unique about human behaviour and the power of ideology and hence we continued our research. We kept finding new material about the SS-men from a wide range of sources including not only official archives but also private collectors who, for example, had diaries and letters written by soldiers at the front. In 2008, we decided that the time had come to apply for funding for a full-scale study of the entire Waffen-SS.