Launched at the West Coast Computer Fair in 1977 - several months after Commodore's PET - the Apple II became the second of the "1977 Trinity", the first three true personal computers which could be taken out of a box, plugged in and operated straight away without a soldering iron or machine-code programming.

It wasn't initially a runaway success and Apple was beginning to struggle financially until the first spreadsheet program - VisiCalc - was launched exclusively for the Apple II in 1979, unintentionally making it the must-have computer of the day and eventually saving the company.