This large Alan Turing website serves as an electronic extension to the original 1983 text. My own publications add new perspectives. The source material has been transformed since 1983. The Scrapbook adds extra comment and illustration, with links.

This Update section will review more systematically, and in roughly chronological order, all those matters where the text of the book can be improved and expanded after some forty years.

It is intended that this section will be developed to absorb the material at present in the Scrapbook. Its informal style suited the early days of the Internet, but is no longer sustainable.

The Update is divided into parts which correspond to the chapters of the book: