Critics consider The Petrified Forest to be Sherwood's most successful play. It is about an intellectual war veteran facing a dangerous gangster in a diner out in the desert. It is available from the Dramatist's Play Service.

Much of Sherwood's information about Lincoln comes from the poet Carl Sandburg's thorough biography, Lincoln: The Prairie Years, which is often bound with the other volume of his biography, The War Years.

Lincoln was very secretive about his family life. The source that most historians begin with for biographical information is the writings of William Herndon (who appears in the play as Billy Herndon). His biography is available as Herndon's Life of Lincoln: The History and Personal Recollections of Abraham Lincoln. A 1997 collection called Herndon's Informants: Letters, Interviews and Statements about Abraham Lincoln explores Herndon's own sources of information.

One of the few...