Sylvia Plath's "Sheep in Fog" explores the speaker's intense feelings of disappointment, despair, and insignificance. The speaker feels like they've been trudging too slowly through life and have failed to live up to their promise and potential. They've let down other people and even fate itself, and they can't see a way forward through the thick, all-consuming fog of their despair. In the end, the poem suggests that the only relief is the oblivion of death, a dark, empty "heaven" where neither expectations nor disappointments exist. Plath wrote the poem shortly before her death in 1962. It was published in 1965 as part of the posthumous collection, Ariel.