On 9 December 1968 hi-tech visionary Douglas Engelbart first used one to demonstrate novel ways of working with computers.
The first mouse that Dr Engelbart used in the demo at the Fall Joint Computer Conference (FJCC) was made of wood and had one button.Much of the technology shown off in the demo inspired the creation of the hardware and software now widely used.
A day of celebration is planned in California to mark the 40th anniversary; with many of the researchers behind the original demo reunited to mark the event.
Paying the price
Office workers using computers constantly are at risk from repetitive strain injury (RSI), more recently known as non-specific arm pain (NSAP)
This is a collection of symptoms covering work-related upper limb problems, which can affect the hands, wrists, necks, arms and upper back
source-BBC and wikipedia