In the years 1965 through 1967, Stan Lee and his art partner Don Heck guided the Avengers through their "Kooky Quartet" era with unbridled adventures and important character development.

Hawkeye, Scarlet Witch, Quicksilver, and Captain America took on all comers, often in multi-part epics that pitted the Avengers against foes old and new, like the Enchantress, Doctor Doom and Kang.

The Avengers of 1965-1967 also featured change within the ranks of the team and its creative stable.

The Wasp and Giant-Man would rejoin Earth's Mightiest-the latter adopting a new costume and codename-and Black Widow and Hercules would join as guest stars.

Lee would depart as writer in the summer of 1966, handing the keys to the Avengers over to newcomer Roy Thomas, whose earliest stories set the stage for his future glories carrying the title to a legacy filled with milestone after milestone.