X-Men #104 (1977) 1st Starjammers! Magneto Restored! Non-GCGed.

In X-Men #104, Erik the Red restores Magneto, who had been reduced to childhood (in a story written by Len Wein that appeared in Defenders #16, Oct. 1974), to adulthood, in the process significantly increasing his powers. However, Erik doesn't return Magneto all the way to his previous age, leaving him instead a comparatively youthful man, which explains how a World War II concentration camp survivor could still be young and vigorous and powerful when he should be extremely elderly.

This issue contains the first appearance of the Starjammers: Ch'od, Cr'reee, but most especially Corsair, who in the fullness of time will be revealed as Christopher Summers, who is Scott Summers' (Cyclops') father.

In this issue, we finally see a somewhat occluded view of the face of the person inside the strange armor who has been haunting Charles Xavier's dreams, and we realize she's female. (Or a really pretty man.) Still no name though.

Jamie Madrox the Multiple Man makes his first appearance in an X-Men comic with this issue. He previously appeared in Giant Size Fantastic Four #4 (Feb. 1975).

This is the first time we see the X-Men's Lockheed SR-71 "Blackbird" jet. They'd previously used a stratojet as air transport; it was destroyed by Count Nefaria in X-Men #94.

This is the first appearance of Moira MacTaggert's research facility/home base, Muir Island. We discover that, among other things, it contains a prison for captured criminal mutants. We learn that Dragonfly, the only female member of Count Nefaria's Ani-Men who fought the X-Men at NORAD in Cheyenne Mountain, after her defeat was imprisoned at Muir Island but managed to escape. According to Brian Cronin's "Comics Should Be Good" blog, the mention of Dragonfly's escape was included in this story because Dave Cockrum had a plan to assemble an all-female superhero team that would have included both Dragonfly and Storm as members. This never happened.

The first hint we have there is a character named Mutant X imprisoned on Muir Island is when we see his cell in this issue; he will not appear in-person until X-Men #125 (Sep. 1979).

The cover to X-Men #104 is a homage to the cover of X-Men #1 (Sep. 1963).

I am very serious that a buyer gets their comic in the condition it was when I sent it. All my comics are mailed inside an acid-free Mylite, with acid-free backing board, inside a Gemini mailer, with two filler pads inside the mailer with the book.

X-Men #104: Cover date April 1977, written by Chris Claremont, penciled by Dave Cockrum, inked by Sam Grainger, lettered by Gaspar Saladino (page 1, uncredited) and Bruce Patterson, colored by Andy Yanchus.