Most of us can hardly remember a time before computers were controlled by mouses. Apple introduced the first popular version with the Mac 30 years ago and it took years before it become other than a niche product. The computer mouse is now a middle-aged rodent of 45. It was introduced as an “x-y position indicator control” on 9 December 1968 by Douglas Engelbert who died earlier this year. Looking at the picture with hindsight, the sixties prototype looks more Mickey than Magic Mouse, but we all have a debt of gratitude to Douglas Engelbert.