The year 2012 has been declared the Turing year because Alan Turing was born in 1912. He died in 1954 at the age of 41 by cyanide poisoning. In his short life Alan Turing has contributed a lot to different areas of science. He got an OBE (Order of the British Empire) for his contribution in breaking the code of the Enigma machine that was used by the Germans during WW II. With other code-breakers at Bletchly Park he designed the bombe an electromechanical machine to discover the settings of the rotors in the German encoders to decrypt their messages. Later he was involved in the Manchester Computers project and he designed his Universal Turing Machine, an abstract computer device. His incentive for this was that he wanted to solve the Entscheidungsproblem as formulated by Hilbert in 1928. His Turing test was designed to define "intelligence": can one distinguish a machine from a human, by just asking questions? This is the start of artificial intelligence. Turing's efforts have certainly contributed to the impetus leading to the development of computers and computer science. All in all, enough reason to celebrate his 100th birthday.
Shortly after Alan's death, his mother wrote the first version of this book. It is a loving account that a mother can give about the much too short life of her famous son. Alan's father was stationed in India and Alan and his older brother John were regularly left in the good care of a family in Scotland while his mother went to accompany his father. So apart from her own memories, Sara also draws on letters from Alan and from other people who have known Alan in his childhood or at a later stage of his life. For example, about his childhood, she mentions that Alan impressed his teachers with his sharp mind. She however mentions also his bad handwriting and his untidiness. She further describes as she had experienced his studies and his career. Obviously for her account of his scientific career, she has to rely even more on letters and testimonies by others. Like in the first edition, also this one contains two unfinished/unpublished texts and correspondence by Alan Turing: one on computing machines and one on morphogenesis, a topic he became interested in lately.
This edition has an introduction by Martin Davis who gives a short survey of Alan's main scientific achievements, and also mentions Alan's homosexuality. In fact Alan's untimely death has been conjectured to be a suicide. Alan's dead body was found with a poisonous half eaten apple nearby (hence the apple on the cover on this edition). Homosexuality still being illegal in those days, explains the intimidation by the police, and this could have been a possible motive for his suicide. Sara never mentions Alan's sexual tendency and considers Alan's death an unfortunate accident. In the afterword, his brother John does confirm Alan's sexual preferences and claims that also his mother knew about it. This is one example where he disagrees with the account of his mother. Sara died in 1976, which allows John in this edition to give his own account of his relationship with Alan, and at several points he places some of the impression given by his mother in a different perspective.
This book is not one in which you will find much details about the scientific work of Alan Turing. This is a somewhat biased account by primary sources, yet with many citations from third persons, about the life of Turing as a person. It is mainly told by a 70 year old loving mother, as a tribute to her son who died too young, but somewhat annotated by the afterword of Alan's brother.