This essay reads James Baldwin’s first novel, Go Tell It on the Mountain, through the lenses of European existentialism and Black existential thought to arrive at a new understanding of the novel itself as well as essential stages of its development. Archival sources and close reading reveal Baldwin’s historically and existentially informed artistic vision, summed up in the terms hindsight and insight. His thoughtful, uncomfortable engagement with the past leads to a recuperated relationship to the community and constitutes existential hindsight, which informs his inward understanding of himself—his insight. This investigation draws on various works from Baldwin’s fiction, essays, interviews, and correspondence to arrive at a better understanding of the writer’s intellectual and artistic development, focusing especially on the professed objectives behind, and major revisions of, the novel. I conclude the essay through a close reading of the conversion scene that constitutes Part Three of Go Tell It on the Mountain.