Few crimes in American history have achieved a notoriety comparable to the murder of a young boy by Nathan Leopold and Richard Loeb in Chicago in 1924.  Leopold, a nineteen-year-old student at the University of Chicago, had fallen in love with Richard Loeb, an eighteen-year-old graduate student in history at the university, and, at Loeb’s suggestion, they had jointly committed the perfect crime: the kidnapping and murder of Loeb’s fourteen-year-old cousin, Bobby Franks.  After pouring acid on the body to prevent identification and concealing it in a drainage pipe, Leopold and Loeb demanded a ransom of $10,000 from the parents of the victim.   But Leopold had dropped his eye-glasses at the scene of the crime; the police had quickly tracked down the killers; and within twenty-four hours of their arrest, both Leopold and Loeb had confessed to the crime.

When I stumbled across the Leopold-Loeb case several years ago – by chance I saw Alfred Hitchcock’s film Rope in a London cinema – only one book had been published on the case.  Hal Higdon had written The Crime of the Century in 1975 and for three decades it had served as an informative and competent account.  But, as I read about the murder, I found myself wanting to know more about the scientific testimony presented in the courtroom.  Clarence Darrow, the most famous attorney in the United States during the 1920s, had taken charge of the boys’ defense in the Cook County Criminal Court.  In July 1924 Darrow called to the witness-stand the leaders of the American psychiatric profession to explain to the court that Leopold and Loeb both suffered from mental illnesses.  In rebuttal, Robert Crowe, the state’s attorney, called his expert witnesses – equally eminent and distinguished psychiatrists – to tell the court that the defendants were entirely normal.

The courtroom proceedings, therefore, consisted solely of scientific testimony.  No one disputed that Leopold and Loeb had committed the murder; the boys cheerfully admitted their guilt and even confessed to the psychiatrists that, if they thought they could get away with it, they would do it again.         

My background is in the history of science – I received my PhD in the subject from Penn – and perhaps only a historian of science could make much sense of the Leopold-Loeb case.  The science of the 1920s was very different from the science of 2008 – in 1924, for example, eugenics was still fashionable – and it is easy, too easy, for historians to dismiss outdated and recondite scientific ideas as so much mumbo-jumbo.  But Darrow’s defense of Leopold and Loeb was entirely scientific; and so, as I started writing the book, it soon became apparent that I would be unable to understand the events subsequent to the murder unless I understood the sciences – psychiatry and endocrinology – that Darrow employed in the courtroom.

My task in this regard was made considerably easier by the preservation at Northwestern University of an astonishing collection of documents on the case.  It is unusual for the transcript of the proceedings of a court case to survive; unless the case is heard on appeal, a transcript is usually discarded as soon as the case is completed; (and since Darrow pleaded Leopold and Loeb guilty there was no possibility that it would be appealed).  Luckily the Leopld family had kept a copy of the transcript of the 1924 hearing and had given it to Elmer Gertz, the lawyer who submitted Leopold’s application for parole in 1958.

On my first visit to Northwestern I discovered, to my surprise and delight, that the university owned, in addition to the transcript of the hearing, a complete set of the confession statements that Leopld and Loeb had made during their first weekend in custody.  These consisted of five hundred pages of interrogation by Crowe, his assistants, and the psychiatrists for the prosecution, and detailed responses by the two prisoners.  Amazingly the university also owned the sole surviving copy of the report made by the defense psychiatrists for Clarence Darrow.  Neither the confession statements nor the psychiatrists’ report had been previously used by historians.

My original aim in writing the book – to construct a narrative that would simultaneously appeal to a popular audience and also address issues current among historians of psychiatry and the law – was facilitated immensely by the wealth of original source material.  The defense psychiatrists wanted to enhance the prestige of their profession and expand the role of psychiatry in the American courtroom; Clarence Darrow aimed to campaign against capital punishment; and state’s attorney Robert Crowe hoped to win election as Chicago’s next mayor if he sent the defendants to the gallows.  Different interests converged on Leopold and Loeb and played themselves out over the summer of 1924.

As I continued my research in the archives it soon became apparent that my book could be shaped as a compelling narrative akin to a murder mystery.  So much day-to-day detail was contained in the primary sources and such a surfeit of information was reported by Chicago’s six daily newspapers that I was able to build a story that carried the reader along with the events I was describing.

The Leopold-Loeb case is a study in depravity, an event that still shocks us today with its callous and cynical brutality.  It is a crime that continues to echo down the years while many other murders – equally brutal but never as calculated and deliberate – have been forgotten.  I hope that For the Thrill of It has done justice to the events it describes.