This third and final volume of Joel Eigen’s study of the English insanity defence is again a scholarly triumph. Following in the vein of Nigel Walker’s inspirational Crime and Insanity in England (1968) and Roger Smith’s path-breaking historical contribution to the sociology of medical knowledge, Trial by Medicine (1981), Mad-Doctors in the Dock covers some of the terrain of Eigen’s two previous studies, Witnessing Insanity (1995) and Unconscious Crime (2003), yet steps back to offer the best available overview of the ways psychiatry entered the courts, and thus expanded its power further into society. The focus of this volume is on psychiatric diagnoses in the Old Bailey, with particular attention paid to delusions, epilepsy and homicidal mania as constructs that were negotiated by psychiatrists, lawyers, judges and the jury in the Central Criminal Court. Beautifully written, Eigen has an unmatched talent for dipping into the details of a particular case to illustrate a general point. This skill can only be realised by someone with a complete comprehension of the subject. His clear voice and great compassion match his fair and thorough treatment of the insanity defence.

Eigen’s work is the result of a lifetime of careful study devoted to one huge data set: the Old Bailey Session Papers (OBSP). Well before they were digitised, he developed a card index system (inherited from Nigel Walker) for comprehending this most complex source in English legal history. He read every trial, and annotated every suggestion of insanity, a total of 994 between 1760 and 1913 – the year when the OBSP ceased publication. That same year, the British Medical Association’s Crime and Insanity Special Committee ceased meeting, delaying the publication of an official report on criminal insanity for ten years. It was not until 1923, in the aftermath of the trial of Ronald True (1922), that the Atkins Committee met to re-evaluate the insanity defence. No one knows the OBSP material like Eigen. Re-reading the transcripts over the course of years of study brings an appreciation of the subject matter far more profound than word-searching the OBSP, now possible at https://www.oldbaileyonline.org.

The key episode in the history of the insanity defence, which has received most scholarly attention, is the formulation of the ‘McNaughtan Rules’ in 1843. Eigen explains: ‘The House of Lords asked the judges who tried McNaughtan to articulate the appropriate grounds for a determination of insanity. Although legal and medical historians have focused most of their attention on “knowing the nature and quality of the act” and “knowing the difference between right and wrong”, the issue that sparked most courtroom debate concerned the actual grounds for medical testimony: could medical witnesses base their conclusions on evidence presented in court?’ (p. 198 n. 5). With typical ease, Eigen reframes the debate around what happened in court, and not on pre-conceived ideas about the legal and medical professions (contained in their respective learned journals).

Although a psychiatric presence had been increasing in court between 1760 and 1843, later psychiatrists needed to be able to articulate their answers about a prisoner’s sanity in terms of the McNaughtan Rules. In many of the trials that Eigen describes we see a co-construction of insanity, with the Law Lords framing the criteria after the trial of Daniel McNaughtan and the physicians following, opining professionally as to whether the defendant knew the quality of their actions, and adding some kind of statement about their sanity. Eigen thus reminds us that insanity is above all a legal construct, in which the psychiatric profession has a regulated role. It did not always work out favourably. Baron Rolfe in the 1847 trial of Boy Allnut for the murder of his grandfather said, ‘the forensic subtlety of our lawyers and the metaphysical dexterity of our modern physicians, have combined to complicate the discussion and [to] leave the uninitiated in hopeless perplexity’ (132). Often the judges and the jury wanted a simple answer, which modern constructions of the insane criminal subject rendered difficult.

The existing historiography typically focuses on struggle between lawyers and physicians, these two worlds coming together in the trading zone of the court, creating a power struggle between two Wittgensteinian language games for the truth of a person’s (in)sanity. These two world-views simultaneously imposed their constructions of reality on the trial. Resisting any Foucauldian reductionism, Eigen importantly focuses on the role of the judge in the management of the trial, and in the framing of medical knowledge in legal terms. Judges were not necessarily hostile, but they guarded the jury’s right to make the final determination about a defendant’s sanity and responsibility. The language games Eigen describes were constantly adjudicated by the Bench, but the jury could further complicate proceedings by ignoring medical testimony in their findings.

Not only does Eigen demonstrate a mastery of the legal thinking on the insanity defence; his history of the professionalisation of psychiatry, employing Bill Bynum and Chris Lawrence’s work, is a lesson in synthetic historiography that could only have been matched by Roy Porter. His discussion of the most notable jurist of his day, James Fitzjames Stephens, is the pinnacle of his thought-provoking concluding chapter. Although there are surely a number of things to be added to this field – such as the effects of the insanity defence in courts other than the Old Bailey (which were felt around the world in many of the English colonies), or expanding the focus to include the period between the two World Wars when there was a move away from using the insanity defence as a way of avoiding the death penalty – all of this future work will be indebted greatly to Eigen’s wonderful study. It is a rare treat to read history this good. Three books of this quality is a far greater career achievement than a market flooded with less substantial scholarship in service of academic metrics.