A history of early business computing in the UK, concentrating on the LEO system designed (and later produced and sold) by Lyons, better known for their chain of teashops at the time.
Entertaining and skilfully written, with lots of information about the people and organisations involved and their motivation. It's rather short on technical detail, but that's excusable as it's intended to be a popular science book rather than a technical history. It's also a bit short of detail on what happened after LEO: there's a lot of attention paid to how the LEO-related companies started building computers, but it feels a bit rushed when it's describing why they stopped.
As with most books on computer history, it's made very clear both how far we've come since the 1950s in some ways, and how, in other ways, so little has changed. Worth reading.