Creator
Dave Cockrum, Len Wein
  
Marv wolfman, Pat Broderick
  
In Comics
Giant-Size X-Men #1 - Deadly Genesis
  
Batman #436 - Year Three Part 1: Different Roads
  
Base
(current) Professor Charles Xaviers Institute for Higher Learning, Salem Center, Westchester County, New York (former) Muir Isle, Scotland,; a loft in Soho, Manhattan, Ust-Ordynski Collective, Lake Baikal, Siberia, U.S.S.R., X-Men Headquarters in Austra
  
Gotham City; Titans Tower, San Francisco