The Uncanny X-Men #221, published by Marvel Comics in September 1987. This key Copper Age X-Men issue features the first full appearance of Mister Sinister (Nathaniel Essex) and is one of the more significant issues from the classic Chris Claremont-era X-Men run.

This is the Direct Edition, professionally graded PSA 9.2 with White Pages. The PSA label specifically notes the first full appearance of Mr. Sinister. A great key issue for X-Men, Mister Sinister, Marvel, and graded-comic collectors.