The origin of Professor X! The birth of the Juggernaut! The end of the Brotherhood of Evil Mutants! The coming of the Sentinels! And the mystery of the Mimic!
Reprints X-Men #11-21. The original X-Men continue the adventures, and meet new adversaries such as Juggernaut, Mimic and the Sentinels! Also includes the origin story of Professor X, and the partial Origin or Beast.