Clive Sinclair in the context of ZX81

The ZX Spectrum (UK: /zɛd ɛks/) is an 8-bit home computer developed and marketed by Sinclair Research. The Spectrum played a pivotal role in the history of personal computers and video games, especially in the United Kingdom. It was one of the all-time bestselling British computers with over five million units sold. It was released in the UK on 23 April 1982, the United States in 1983, and Europe in 1984.

The machine was designed by the English entrepreneur and inventor Sir Clive Sinclair and his small team in Cambridge, and was manufactured in Dundee, Scotland by Timex Corporation. It was made to be small, simple, and most importantly inexpensive, with as few components as possible. The addendum "Spectrum" was chosen to highlight the machine's colour display, which differed from the black-and-white display of its predecessor, the ZX81. Rick Dickinson designed its distinctive case, rainbow motif, and rubber keyboard. Video output is transmitted to a television set rather than a dedicated monitor, while application software is loaded and saved onto compact audio cassettes.

Sinclair Research Ltd is a British consumer electronics company founded by Clive Sinclair in Cambridge in the 1970s. In 1980, the company entered the home computer market with the ZX80 at £99.95, at that time the cheapest personal computer for sale in the United Kingdom. A year later, the ZX81 became available through retailers, introducing home computing to a generation, with more than 1.5 million sold. In 1982 the ZX Spectrum was released, becoming the UK's best selling computer, and competing aggressively against Commodore and Amstrad.

A combination of the failures of the Sinclair QL computer and the TV80 pocket television led to financial difficulties in 1985, and a year later Sinclair sold the rights to its computer products and brand name to Amstrad. Sinclair Research Ltd continued to exist as a one-man company, marketing Clive Sinclair's inventions.