Sourcehttp://en.wikipedia.org/wiki/Xerox_PARCFounded in 1970 as a division of Xerox Corporation, PARC has been responsible for such well known and important developments as laser printing, the Ethernet, the modern personal computer graphical user interface (GUI), ubiquitous computing, and advancing very-large-scale-integration (VLSI).
and the source http://en.wikipedia.org/wiki/PARC_(company)#Adoption_by_AppleAdoption by Apple
The first successful commercial GUI product was the Apple Macintosh, which was heavily inspired by PARC's work; Xerox was allowed to buy pre-IPO stock from Apple in exchange for engineer visits and an understanding that Apple would create a GUI product. Much later, in the midst of the Apple v. Microsoft lawsuit in which Apple accused Microsoft of violating its copyright by appropriating the use of the "look and feel" of the Macintosh GUI, Xerox also sued Apple on the same grounds. The lawsuit was dismissed because Xerox had waited too long to file suit, and the statute of limitations had expired.