I'm impressed that so many mentioned Trad.Anon. It's intriguing to the mind that somebody wrote/rewrote those songs. Also note that some songs have been published under Anon and the author got shafted.(Carl T Sprague/ When the Work's All Done this Fall.)Or, published under some name that didn't belong there such as what happened to most of Louis Jordan's stuff. I would also include Robert Hunter both with Jerry Garcia and otherwise. Dylan recorded two of Hunter's on one of his latest albums. Also Doc Pomus, Felice and Boudeleaux Bryant, Roy Orbison, Jimmy Driftwood, J.J.Cale, and Huddie Ledbetter.