X-Men: Target: Angel (Digest)
Chris Claremont (Writer), Paul Smith and Walt Simonson (Artists)
Mutants. Children of evolution. Gathered together by telepath Professor Charles Xavier, the X-Men are sworn to protect a world that fears and hates them. Now one of their number - the winged mutant known as Angel - is missing! Weakened by their battle with the drooling alien Brood, his comrades must descend to the darkest nether reaches of the city. Here, they encounter a mysterious underground race known as the Morlocks. Battling a menace they cannot defeat, it appears that these dank catacombs may well become the final resting place of the Uncanny X-Men.
Uncanny X-Men #167-173
Part of Marvel's "Backpack Marvels" prints. Meaning it is all in black and white and it is much smaller than a regular trade paperback.