The Avengers #66
Avengers #66 holds a singular place in Marvel history as the issue where writer Roy Thomas introduced adamantium — a name and concept that would eventually become one of the most recognizable materials in all of superhero fiction, most famously due to its later bonding to Wolverine's skeleton. At the time of publication, the metal served an immediate narrative purpose: Thomas constructed an entire issue around demonstrating the cylinder's indestructibility against the combined might of Thor, Iron Man, and Goliath, only to deliver a gut-punch reveal when the Vision — under Ultron's mental control — steals it to rebuild their most dangerous enemy yet as Ultron-6. The issue also marks the formal return of Thor and Iron Man to active Avengers membership after years of editorial exile, and introduces metallurgist Myron MacLain, a character whose retconned wartime history would later tie adamantium's creation directly to the origin of Captain America's shield.
In "Betrayal!", the Avengers face their most dangerous foe yet as they confront Ultron-6, a relentless machine of destruction. With Iron Man and Thor back in the fold after their time away, the team races to stop a deadly Adamantium cylinder forged by the twisted genius Myron MacLain. Written by Roy Thomas and brought to life by Barry Smith’s dynamic art, with inks by Syd Shores and letters by Artie Simek, this 1969 classic features a cover by John Buscema and Sam Grainger.
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The story, titled 'Betrayal!', was written by Roy Thomas and penciled by a nineteen-year-old Barry Windsor-Smith — then credited simply as Barry Smith — one of his earliest assignments at Marvel, completed after he had returned to the United Kingdom. Thomas assigned Windsor-Smith to interior art on issues #66 and #67, while the cover was provided by John Buscema, the series' prior regular penciler; Windsor-Smith had prepared his own cover for the issue, but it was rejected and only surfaced publicly decades later in Comic Book Artist Vol. 1 #2. Windsor-Smith's interior work at this stage was visibly shaped by Jack Kirby and Jim Steranko — influences evident in the opening Thor splash page and in the graphic, countdown-structured layout on pages 10–11 — and was inked throughout by veteran Syd Shores, with Stan Lee serving as editor. The issue was part of a three-chapter Ultron storyline, Thomas's second extended Ultron arc.
Trivia · 8 facts
- First appearance of adamantium in the Marvel Universe, introduced by writer Roy Thomas in a story scripted for the July 1969 cover-dated issue (released May 1969).
- First appearance of Dr. Myron MacLain, the metallurgist who created adamantium and who would later be retconned as the same scientist responsible for forging Captain America's Vibranium-steel shield during World War II.
- First appearance of Ultron-6, the rebuilt, adamantium-shelled incarnation of Ultron, whose near-invulnerability drives the subsequent issue's conflict.
- Thor and Iron Man formally rejoin the Avengers' active roster in this issue, their absence having been editorially mandated by Stan Lee since issue #16 (1965).
- Interior pencils by Barry Windsor-Smith (then Barry Smith), one of his earliest Marvel assignments; the published cover was by John Buscema, replacing a Windsor-Smith cover that was rejected and first published in Comic Book Artist Vol. 1 #2.
- The creative team on interior art was Roy Thomas (writer), Barry Windsor-Smith (penciler), Syd Shores (inker), and Artie Simek (letterer), with Stan Lee as editor.
- The story opens part one of a three-issue Ultron arc (continuing through Avengers #67–68), in which the Vision is mentally commandeered by Ultron to steal the adamantium cylinder from aboard the S.H.I.E.L.D. Helicarrier.
- The issue has been reprinted in Marvel Super Action #27, Marvel Masterworks: Avengers Vol. 7, and Essential Avengers TPB Vol. 3.
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Reprints
Reprinted in Astounding Stories #76 (1971), Hit Comics Die Rächer #211 (1971), Die ruhmreichen Rächer #65 (1977), Les Vengeurs #1 (1980), Marvel Super Action #27 (1981), Los Vengadores #66 (1982), Essential Avengers #3 (2001), Essential Avengers #3 [2010 Edition] (2010), Marvel Gold. Los Vengadores: La Batalla por La Tierra #[nn] (2013), Avengers Epic Collection #4 (2015), The Avengers Omnibus #3 (2018), Marvel Creator Collection #1 (2025), HIP Classics #19157, Il Mitico Thor #82
Key issues in The Avengers
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