The history of the computer is entwined with that of the modern world and with the life of one man, the brilliant but troubled Alan Turing.

How did the computer come to structure and dominate our lives so totally? In Jon Agar's enlightening story of the `universal machine', we discover how Turing's groundbreaking work not only helped break German codes during the Second World War but also founded the beginnings of the modern computer.

Persecuted by the authorities for his homosexuality, and ultimately hounded to suicide, Turing's personal tribulations are as relevant to the modern world as his work on computing, as indicated by his posthumous royal pardon of 2013 and the recent film The Imitation Game, which focuses on Turing's turbulent life.