Hemingway published Two non-fiction books during his lifetime: Death in the Afternoon and Green Hills of Africa.
Death in the Afternoon, published in 1932, examines Spanish bullfighting while also reflecting on courage, ritual, art, and the writer’s role as an observer. Green Hills of Africa followed in 1935 and drew on Hemingway’s experiences on safari in East Africa, blending travel writing, hunting narrative, and literary reflection.
The number becomes confusing because Hemingway’s bibliography contains many additional non-fiction titles, including A Moveable Feast and The Dangerous Summer. Several of those appeared after his death in 1961, often from manuscripts or unfinished material. The question’s phrase “during his lifetime” is therefore essential: the standard bibliographic count is two nonfiction works published while he was alive.