Steve Jobs left Apple in 1985. And used $12 million of his own money to start a new computer company called NeXT. With NeXT Steve Jobs could regain the control he lost at Apple. Unfortunately, NeXT's computers were expensive and never found massive success. But the NeXTSTEP operating system, built on top of UNIX, was used as the foundation for Mac OS X. 18 years and 14 versions later millions are still using it.