In the 1940s, a British catering company identified the part that only a computer could play in running its business. Since no such computer existed or was in prospect, it set about designing and building a business computer of its own. This book is a first-hand account of how this came about. The narrative sketches the 20-year life and times of LEO, the computer and organization that resulted. It tells of the trip to the USA in 1947 to discover the truth about the Electronic Brain that was being built for ballistic studies. It goes on to relate how a machine specially attuned to the more exacting demands of time-critical office work was built and programmed, leading to the running of the world's first regular, routine, business application in November 1951. There are individual accounts of some of the earliest jobs written by the consultants who brought them to fruition. The book concludes with the different strands coming together to provide the essence of the LEO credo of comprehensive, integrated, secure, action-stimulating implementations.