The year 2012 saw the centenary of the birth of Alan Turing, one of the founders of computer science. There were many conferences held in Turing’s memory, and Cambridge University Press decided to use the occasion to republish the biography of Turing written by his mother in 1959 after his early death five years before. The original biography is not hard to find and much of the detail it offers about Turing’s life has been incorporated in the substantial biography of Turing by Andrew Hodges, *Alan Turing: The Enigma *(originally published in 1983). The question, then, is what the new edition of Sara Turing’s biography has to offer that was not already available.

First, it is worth saying a word about what Sara Turing said and what she did not say. Two of the respects in which Turing has been of interest even more of recent years than during his lifetime were his work in cryptanalysis for the British government at Bletchley Park during the Second World War and his homosexuality. Sara Turing was aware of Turing’s war work, but she was scarcely in a position to say anything of substance about it. This was not for lack of effort on her part; laws relating to the confidentiality of the work would have kept anyone at the time from learning or writing about Turing’s work. The release of information about the project at Bletchley Park gives the reader today many places to learn about the individuals assembled as part of that project and Turing’s leading role in directing their efforts.

The legal penalties associated with practicing homosexuality in England in the 1950s tripped Turing up and led to his being convicted in a court of law. The penalty associated with the conviction involved a treatment with hormone therapy (an alternative to a term in prison). Turing apparently died from consuming cyanide in 1954, and the argument has been made that this was suicide while his mind was unbalanced as a result of the therapy. Since Turing’s mother does not mention the homosexuality and the treatment, she offers the reader the suggestion that it may have been an accident. Even if that is a possibility, it is hard to make a convincing case if one ignores the medical and psychological effects of what Turing had gone through. Presumably Turing’s mother was aware of the legal decision and saw fit not to mention it in a biography of a son to whose memory she was devoted.

What this biography has offered since its first appearance is a family history, a picture of Turing as he grew up and went to school. Those who are inclined to deride British public schools between the world wars can learn here about the extent to which Sherborne, in particular, managed not to make life a hell for Turing, as one might have expected. The names of teachers and headmasters are trotted out with praise for their ability to deal with a duck as odd as Turing. The author describes his years at Cambridge and his trips to the United States, primarily from the social point of view, and her account of the time at Bletchley Park is almost entertaining for how little she could say about what he was doing. In the same way, she could admire his work on the development of the computer after the war without herself being able to comment on anything technical. To make up for that, she included two chapters, one on “computing machinery” and one on morphogenesis, the latter a subject to which Turing devoted a good deal of time during his later years (few as those were). The value of these chapters comes largely from the extent to which the text is provided by others, including Turing himself.

What does the new edition offer, then? It begins with a foreword by Martin Davis, whose work on the history of logic (*The Universal Computer*) has the subtitle *From Leibniz to Turing*. Davis offers a brief summary of the aspects of Turing’s life largely or entirely omitted in the biography, although they can be found in Hodges’s book. What comes as something of a surprise is the concluding section of the new edition, entitled “My Brother Alan” and written by Turing’s brother John. The justification for this edition must come from the first appearance in print of this material, much of which can be regarded as a reply to his mother’s account. When this material was offered to Cambridge University Press, there was still some editorial work to be done, and there is a resulting lack of uniformity in this section.

“My Brother Alan” expresses John Turing’s antipathy toward many of his brother’s personal characteristics and paints them in a light less favorable than the previous pages do. In fact, he is also ready to challenge his mother’s account of the atmosphere within the family, one of the areas in which she might have been expected to be a reliable guide. John Turing suggests that his mother may have joined in some of the chorus of praise for Turing after his accomplishments rather than encouraging him before. He also looks for biographical sources for Turing’s homosexuality, and describes his own reactions to Turing’s legal difficulties. He does not come across as particularly sympathetic, but argues that Turing put too much of a strain on even his family’s support.

One does not need to turn to this new edition of the biography of Alan Turing by his mother for the sake of insights into his technical accomplishments in mathematics, computer science, or morphogenesis. In addition to Hodges’s biography, there is a good deal of work from the pen of B. Jack Copeland (such as *The Essential Turing *from 2004) and even Turing’s dissertation has now been published by Princeton University Press. What Sara Turing’s biography, now joined by the pages from her other son, has to offer is a picture of the English society amid which Turing lived and worked. Those who seek to understand the basis for some the decisions that he made in his life, if not for his intellectual achievements, can benefit from these Turing family recollections.

Thomas Drucker has taught in the Department of Mathematical and Computer Sciences at the University of Wisconsin–Whitewater since 2001. He had previously taught at the University of Wisconsin–Extension and Dickinson College. He is Program Director for the Philosophy of Mathematics Special Interest Group of the MAA and was editor of the Bulletin of the Canadian Society for History and Philosophy of Mathematics for several years. He edited *Perspectives on the History of Mathematical Logic* (published by Birkhäuser in 1991 and reprinted in 2008) and has written and spoken elsewhere on Turing. His most recent article dealt with mathematics in the Savoy operas.