Make your own free website on
Designing the LEO I

LEO: The rise and fall of the world's first business computer

I think we may be on the threshold of office management... The principal reason for this is obvious enough - namely that we are well and truly embarked on the construction of LEO, the Lyons Electronic Office, and if this venture is a success it is bound to have a profound effect... Possibilities introduced by LEO may, if we dare to venture, lead us to God knows where... (John Simmons 1950)

Chronicled in the pages of this website, is the history of the LEO I, the computer funded and built by Lyons in order to improve efficiency in their office, it became the first business computer the world had ever seen, and spawned a series of successors as well as Leo Computers Inc.


The history of J. Lyons & Co. The company which first built the LEO I


The history behind the worlds first business computer, and the reasons behind its creation


The backup/succesor to LEO I. This page chronicles the building of the second computer by Lyons, as well as the subsequent formation of Leo Computers Inc. the company which would go on to build LEOs for other customers around the world


The second age of computers brought with it the most advanced LEO computers yet, and also saw the end of an era in terms of Leo Computers.


The construction of LEO was based on the early work of a number of people and their computers. Here we look at some of those machines, as well as the closest rival for LEO I - UNIVAC.

Sounds of the LEO

A recording of sounds made by the LEO III


Links to a number of pages including the LEO society website, and a simulator of the LEO I itself.