X-Men #15

Published in 1965, X-Men #15 arrived during the early years of Marvel's Silver Age, a period defined by the expansion of the mutant mythos under the creative direction of Stan Lee and Jack Kirby. This issue is particularly notable for featuring the debut of the Sentinels, the towering mutant-hunting robots that would become central antagonists in the series. The concept introduced a recurring thematic thread regarding prejudice and the societal fear of the 'other' that remains a cornerstone of the X-Men narrative.

The interior art was provided by Jack Kirby, with inks by Vince Colletta and a script by Roy Thomas, who was beginning to take a larger role in the writing duties. Kirby’s design for the Sentinels—clunky, imposing, and technologically menacing—perfectly captured the mid-century anxiety toward unchecked technology and state-sponsored surveillance. The issue was well-regarded by readers for escalating the stakes of the series, moving the team from small-scale encounters toward the epic, high-concept threats that eventually defined the franchise.