In 1952, LIFE sent legendary photographer Alfred Eisenstaedt to Cuba to shoot author Ernest Hemingway. The magazine needed photos to run alongside a new novella that would run in LIFE before it was published in book format. That book was “The Old Man and the Sea,” and the issue of LIFE where it was first printed went on to sell 5.3 million copies in two days.

For years afterward, Eisenstaedt would refer to the experience of shooting “Papa” Hemingway as his most difficult assignment ever. Recently, LIFE discovered these photos, all but two of which have never been seen: LIFE’s editors opted to print illustrations based on the pictures rather than the pictures themselves.