The dramatic title and the true crime billing do this book somewhat of an injustice. Margalit Fox isn't writing in the traditional true crime genre, not being particularly interested in solving the 1908 murder of the elderly Scottish spinster Marion Gilchrist. (Indeed, while a brutal crime, Gilchrist's murder is perhaps just as horrifying in its banality—were it not for Arthur Conan Doyle's later involvement, her name would long since be forgotten.)

Fox is far more interested in exploring what the subsequent trial of Gilchrist's alleged killer tells us about Edwardian Britain, which Fox presents as a transitional period between "the twilight of nineteenth-century gentility and the upheavals of twentieth-century modernity." Oscar Slater was convicted of Gilchrist's murder and sentenced to death (later commuted to life and hard labour) although it was patently obvious that Slater was innocent, the charges against him trumped up because he was a foreigner and a Jew. It would take 20 years and the intervention of Arthur Conan Doyle—best known as the creator of Sherlock Holmes—to secure Slater's release from prison.

Don't go into this expecting a page-turning procedural, but as an exploration of how prejudice leads to miscarriages of justice, Conan Doyle for the Defense is quite engaging.