I'm reading A Moveable Feast as I planned and ran across an interesting anecdote about My Old Man. Hemingway's wife was meeting him in Lausanne and decided to bring his entire unpublished oeuvre with her, complete with carbons. The suitcase was stolen in Gare du Nord and never recovered.
The only survivor was My Old Man which was in the mail, rejected by a magazine editor. The story made it into the anthology of Best Short Stories for the year, even though the editor stretched a point by including it, as it hadn't been published in a magazine first.