Jack Copeland is Professor of Philosophy at the University of Canterbury in New Zealand and Director of the Turing Archive for the History of Computing, and has been studying the history of Bletchley Park since 1992. He is a contributor to Scientific American and his previous publications include Artificial Intelligence, (Blackwell, 1993), Logic and Reality (OUP, 1996), Turing's Machines (OUP, forthcoming), The Essential Turing (OUP, 2004), and Alan Turing's Automatic Computing Engine (OUP, 2005).