Book excerpt: Secret wartime projects in code-breaking, radar and ballistics produced a wealth of ideas and technologies that kick-started the development of digital computers. This is the story of the people and projects that flourished in the post-war period. By 1955 computers had begun to appear in the market-place. The Information Age was dawning and Alan Turing and his contemporaries held centre stage. Their influence is still discernable deep down within today's hardware and software.