Scientific content is not neglected; Leavitt's discussion of Turing's 1936 paper has perhaps excessive technical detail. But the vision is partial: he fails to give any discussion of what Turing's proof implies for the question of artificial intelligence. A general problem is that, being the prisoner of secondary sources, the author finds himself the outsider. He quotes from another writer on statistical methods in 19th-century code breaking but omits the primary fact that Turing's central scientific contribution at Bletchley Park, the British wartime cryptanalytic center, was his statistical theory of weighing evidence. The book's subtitle is "Alan Turing and the Invention of the Computer," but on the critical question of Turing's relationship with von Neumann it must rely on quoting Martin Davis's Engines of Logic.

This is no groundbreaking book, nor does it do much hoeing or weeding. It is a survey of a field long cultivated by other hands, devoid of new witnesses. The title, also secondhand, suggests new light on his death, but there are no new facts. Leavitt claims a "sad descent into grief and madness" induced by the prosecution--he ignores the heap of manuscripts from Turing's last prolific year of research and misrepresents his renewed interest in physics as ravings. No new revelation about Turing's code breaking is offered. Leavitt describes his visit to Bletchley Park--now a museum--but only as a tourist, to report the embarrassment of a tour guide in describing Turing's fate. In this book, Leavitt offers his own tour. It is one that many will find congenial and that will at least introduce new readers to the still tingling enigma of Alan Turing.

This article was originally published with the title A Tour of Turing.

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