From Mac Guides
NeXT was a computer company founded by Steve Jobs in 1986. It was noted for its revolutionary operating system that was based on the Mach microkernel. The first operating system release was NeXTSTEP, which was fully object-oriented and amazingly fast for the 68030 processor that it used. Other notable features were the use of the Objective-C programming language and Display PostScript.
In 1985, Steve Jobs was stripped of his CEO duties, being exiled to what he called 'Siberia' at Apple Computer due to an internal power struggle against John Sculley. He soon resigned, and the next year, he and a few ex-Apple employees founded NeXT Computer Inc. Apple quickly initiated a lawsuit with NeXT, which resulted in an out of court settlement restricting NeXT to the workstation market.
In 1989, the NeXT computer was finally released after much speculation. However, after selling just 50,000 computers in 4 years, NeXT began to focus on its software in 1993.
Acquisition by Apple
NeXT's fate changed when the company was purchased by Apple in 1996 for $402 million. Steve Jobs returned to Apple as a consultant, and later became interim CEO. Finally, at the MacWorld Expo in January 2000, Steve Jobs become Apple's permanent CEO.
Influence on Apple today
Much of NeXT's work can be seen in Apple's software today. Mac OS X is heavily based on NeXTSTEP, and the API, now named Cocoa, is used by a large number of Mac OS X developers. NeXT's WebObjects technology is also still in use, powering, among other things, the popular iTunes Music Store. Also, several details from NeXTSTEP can be seen in the Mac OS today, such as the font selector and alert noises.
Just after the release of the first NeXT computer, Steve Jobs was quoted as saying "this will either be the last machine to make it, or the first to fail", commenting on the stratification of the market. In hindsight, his statement is quite correct, with the computers selling much worse than expected.
NeXTSTEP included as one of it's alert noises, "Ni" from the movie, "Monty Python and the Holy Grail."