This is a great book by Jack Copeland. It not only explains the Alan Turing's live but also most of the history of the Manchester Computer. It goes far beyond the movie "The imitation game", which by the way was a great movie.
Alan Turing was a pioneer with his Machine, that helped to solve the Entscheidungsproblem, was crucial to break the german codes during the second world war, was the father of the Artificial Intelligence and much more.
The idea of the Turing Machine, described in 1936, before any computer was made is simply amazing. The idea of storing a program in the memory is now trivial but it wasn't at that time where not even the computers existed.
The book is nice to read and it gives you the perspective of what they had and what we have nowadays.