First 15 cent issue. "Betrayal!" Part 1 of 3. First appearance and use of adamantium. Script by Roy Thomas. Pencils by Barry Windsor-Smith. Inks by Syd Shores. Cover by John Buscema and Sam Grainger. Onboard the SHIELD Helicarrier, Earth's Mightiest Heroes test a new metal alloy called adamantium! The metal is so strong that even Thor's hammer cannot fracture it! Wow, what would happen if this awesome alloy fell into the wrong hands? Regrettably the Avengers don't have to wait long for the answer as the Vision steals the adamantium and then ambushes his fellow avengers inside the mansion! What a shocking development! Could things get any worse? Perhaps only if the Vision's robotic creator were to suddenly appear! An excellent issue! Cameo appearance by Ultron-6. Avengers Lineup: Goliath, Iron Man, Thor, Vision, Wasp, and Yellowjacket. (Notes: Ultron previously appeared (as Ultron-5) in Avengers 57. This is the first of the five issues that Barry Windsor-Smith drew for the Avengers title (1st series): issues 66, 67, 98, 99, and 100. The letters page includes a letter from writer James Van Hise. This story was reprinted in Marvel Super Action 27.) 32 pages. Cover price $0.15.