Uncanny X-men 1

#8 Comic to Own for Phoenix Fans - Uncanny X-men #1

Of course this issue is beyond the budget of most collectors but it has to be in the top 10 because it introduces Jean Grey as Marvel Girl for the first time ever. You can pick this issue up in various trade paperbacks.

At Xavier’s School for Gifted Youngsters in Westchester County, New York, Professor Charles Xavier summons his students telepathically. When the Beast, Angel, Iceman, and Cyclops[1] arrive, he puts them through a series of exercises to hone their mutant talents. Xavier then introduces them to a new student, Marvel Girl, to whom he explains the purpose of his school: his students do receive an education, but they are also the first line of defense against evil mutants.

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