In Margaret Atwood's Oryx and Crake, Jimmy is known after the apocalypse as Snowman. The name is short for “Snowman the Jimmy,” and it reflects his isolated existence after a catastrophe has apparently eliminated most of humanity.
Jimmy's earlier life is connected to the corporate compounds of a technologically advanced but deeply unequal society. He becomes friends with Crake and falls in love with Oryx, while Crake develops the genetically engineered Crakers and plans a radical transformation of human life.
The novel alternates between Snowman's present and Jimmy's past. This structure gradually reveals how the world ended and why Snowman is left caring for the Crakers. The character's two names therefore mark two stages of his identity: Jimmy belongs to the old world, while Snowman survives in its aftermath.
The title names the other two central figures. Crake is Jimmy's brilliant friend, and Oryx is a teacher and performer whom both men know. Neither is the protagonist's post-apocalyptic name.