Giant-Size X-Men #1 (1975) 1st Storm, Nightcrawler, Colossus, Thunderbird, 2nd Wolverine! GCG 9.0.

In the mid-1970s, Marvel Comics was trying hard to increase its international sales. The X-Men at the time had been a reprint book for years - the last original-story X-Men issue was #66 (Mar. 1970). Thus the decision was made to begin producing new X-Men stories, but with a significantly "international" membership. This, hopefully, would lead to higher international sales.

Casting about through the X-Men's history for characters meeting the "international" definition, they found Banshee, Sean Cassidy, an Irishman with a "sonic scream" who'd previously appeared in one issue, X-Men #28 (Jan. 1967).

Similarly mined from back issues was the Japanese character Sunfire introduced in X-Men #64 (Jan. 1970); not a team player, he wouldn't last long.

That was pretty much it for "international" characters previously appearing in the series. Thus new characters needed to be created. Though not technically "international," the Native American hero Thunderbird would likewise not last long.

Among characters who would last, and become very important to the history of the X-Men, and Marvel Comics in general, came Storm, Ororo Munroe, who was ostensibly Kenyan, to hopefully boost sales in Africa.

Nightcrawler, Kurt Wagner, was German.

Colossus, Piotr Rasputin, was Russian. His younger sister, first appearing though unnamed in this story (she would not, in fact, be named for another six years, in Uncanny X-Men #145, May 1981) would be given the name Illyana Rasputin and eventually become the hero Magik.

Of course the biggie, the most popular of the New X-Men, as fans would come to call the team, was the Canadian, Wolverine a.k.a. Logan, a character created a few months before by writer Len Wein. Though The Incredible Hulk #181 (Nov. 1974) is commonly referred to as Wolverine's first appearance, it's worth noting this was actually his first FULL appearance; he'd appeared in cameo, in the last panel of the previous issue, #180. Though in my listing here I've defaulted to the commonly-repeated "fact" that Giant-Size X-Men #1 is the second appearance of Wolverine, I will be the first to admit it's arguably his third.

The original team members do all appear at the end of the story.

At the time Marvel was going though a period where they regularly released "Giant-Size" issues of their most popular titles. These were thick, "square" comic books with a much higher-than-normal page count. The original plan for the New X-Men was that, after Giant-Size X-Men #1, they would have continued on as a series of Giant-Size books, published quarterly. Also the series would have combined the original members with the new members in one team. When sales figures for Giant-Size X-Men #1 showed it was a surprise hit, Marvel decided, rather than producing more high-page-count quarterlies, to switch The X-Men from being a reprint book over to new stories. The much-smaller page count of a standard-size comic book however necessitated a streamlined membership, thus all the original team members (except Cyclops) as well as Sunfire were written out.

It's amusing to know one of the main reasons that, of all the original members, the only one who made the cut onto the new team was Cyclops was because artist Dave Cockrum had come up with a new, awesome design for Cyclops' visor that he REALLY wanted to draw. In addition to all its other "firsts," Giant-Size X-Men #1 marks the first appearance of the new visor.

Thus we have the interesting fact that the first appearance of the "All-New, All-Different X-Men" was not in The X-Men #94, the first non-reprint issue in five years, but rather in the stand-alone Giant-Size X-Men #1.

Cover date 1975 (on-sale date February 25, 1975; there is no date actually printed on the cover beyond "1975" though it has been listed as May 1975 in later reprints, of which there have been many; a book's cover date is generally when it comes OFF the stands, not when it goes on-sale, and since a quarterly book released in February would have come off the stands three months later in May, this makes sense), plotted and written by Len Wein with an uncredited plot assist by Chris Claremont, penciled and inked by Dave Cockrum, lettered by John Costanza, colored by Glynis Wein.