I recently read Ronald Hayman's biography of Sartre and, simultaneously, "followed along" in an English translation of Sartre's "Wartime Diaries."
The two texts together gave me a powerful, personal and enlarged new look at Sartre's ideas about the hero and the coward.
Just a suggestion. You may already have read the Hayman book.
An interesting ( and not entirely favorable) comment on it can be found here: