David Leavitt, The Man who Knew too Much, Alan Turing and the Invention of the Computer (2005) 280p.

Alan Turing disappeared from the annals of the electronic computer because of his elegedly homosexuality, but in fact was one of the founding fathers of the electronic computer. David Leavitt’s book is a typical American biography reclaiming Turing’s place in that history. The book reads very easily and was written with skill, despite that it never reaches a depth that does honor to Alan Turing’s intellectual contribution to rise of the computerized era we live in, neither technically nor personally. Undoubtfully, this flaw is due to Leavitt’s merit of being a generalist with an interest in a widest variety of topics. This book is therefore not more than an introduction in the complex and long history of the invention of the computer, but a pleasantly written one.

Turing is best known for the Turing Machine, but his most important work might well have been his least known work on the bombe, a machine first built by Polish engineers to crack the German Enigma code, but greatly improved by Turing. Least known, because work on breaking the Enigma code was governed by the war secrecy. Leavitt’s red threat and argument (each book needs a twist say American publishers) is the parallel and correlation between Turing’s life as a homosexual and his work as a mathematician on his thinking machines. Leavitt argues that Turing must have been driven by the absence of ideal love in his life, a void he attempted to fill by the creation of a man-machine. I personally have trouble understanding why homosexuality is always considered to be the one and only motivation for all excentricism and genius in homosexual men, making it the one-dimensional cause for a sickness of the heart that expresses itself in the genius of the mind. I find this an over-idealization of homosexuality that is itself outside the extrordinary, and Leavitt was tempted to follow this one-dimensional clue too easily.

More interesting are the chapters on the actual technical and mathematical contributions by Turing, and although the chapters on Turing’s 1936 paper that deals with the Universal Machine, entitled On Computable Numbers, with an Application to the Entscheidungsproblem reach some technical depth, in general the book lacks true substance.

Alan Turing’s contribution to the development of the electronic computer becomes fully clear nevertheless, although the book perhaps over-emphasizes the role Turing played and under-plays the role of the conditions and simultaneous discoveries, again in a typical American fashion. Turing contributed to the development of the bombe, the ACE (Britain’s premier electronic computer), and the Manchester Mark I, and should be considered part of the generation of pioneers that contributed to the origin of the electronic computer.