Earth’s Mightiest Heroes are matched with two of comics’ mightiest talents — Roy Thomas and John Buscema — for one of the most creative periods in Avengers history! There are cover-to-cover watershed moments: Hercules goes mano-a-mano with Dragon Man! Captain America mixes it up with the Russian Red Guardian! The mantle of the Black Knight is redeemed! Quicksilver and Scarlet Witch defect and rejoin Magneto’s Brotherhood of Evil Mutants! Black Panther joins the team! The Avengers battle the X-Men! An all-new Masters of Evil makes the scene! Bucky Barnes’ tragic death is recounted for the first time! A reality-bending battle pits the new Avengers against the original Avengers! And the sinister Ultron debuts! Collecting AVENGERS (1963) #41-56 and ANNUAL #1-2, X-MEN (1963) #45, and material from NOT BRAND ECHH #5 and #8.