Uncanny X-Men Vol.1 #104
You knew it had to happen sooner or later, the all new X-Men must battle the team's oldest and most dangerous adversary - Magneto, the Master of Magnetism! Plus, who are the Starjammers, and what is Mutant X?
Printed: Apr 1977
Writers: Chris Claremont
Art: Dave Cockrum and Sam Grainger
Cover: Dave Cockrum