Giant-Size X-Men #1 is a special issue of the X-Men comic book series, published by Marvel Comics in 1975. It was written by Len Wein and illustrated by Dave Cockrum. Chris Claremont contributed to the plot, having conceived the idea of Polaris using her powers to propel Krakoa into space, though he went uncredited.
Though not a regular issue, it featured the first new X-Men story in five years, titled "Second Genesis." The issue serves as a bridge between the original X-Men and a new team. Chronologically, it is placed after X-Men #66 and before X-Men #94.
The 68-page book was published with a May 1975 cover date and was distributed to newsstands in February of that year. It has been cited as a starting point of the Bronze Age of comics and is notable for expanding the X-Men's roster beyond a white American cast to a more international lineup. This was an effort to appeal to a broader, global audience, although some characters were initially portrayed in a stereotypical manner.

MARVEL - GIANT SIZE X-MEN (ENGLISH) (1975) 1 is categorised COMIC BOOKS / BACK ISSUES and sold by l'Imaginaire, a store and specialised website.