Boleslav William Felix Robert Sienkiewicz is an American artist known for his work in comic books—particularly for Marvel Comics' New Mutants, Moon Knight, and Elektra: Assassin. He is the co-creator of the character David Haller / Legion, the basis for the FX television series Legion.

Moon Knight is a character appearing in American comic books published by Marvel Comics. Created by writer Doug Moench and artist Don Perlin, the character first appeared in Werewolf by Night #32.