You are on the Book Update section of my large Alan Turing website. This Book Update takes the role of a new preface to the book, and a guide to developments since its first edition in 1983.
This Update is incomplete and is always under development.
The Alan Turing Internet Scrapbook also has much new material, with links to other websites which relate his life and work to present-day developments.
I thank the many readers of my book whose messages have helped me to build up this material.