Shel wrote many songs, including the entire "Cover Of The Rolling Stone" album for Dr. Hook.
http://homepage.ntlworld.com/peter.dukes3/shel.htm
http://www.geocities.com/SunsetStrip/Club/6166/ss/ssbio.html
In the late 1960s Silverstein became also known for being a composer and lyricist of songs, including "A Boy Named Sue" (sung by Johnny Cash, 1969), "One's On The Way", "The Unicorn" (sung by the Irish Rovers), "Boa Constrictor", "So Good To So Bad", "Sylvia's Mother" (sung by Dr. Hook, 1972), "The Great Conch Train Robbery", and "Yes, Mr. Rogers".
Albums of Silverstein's songs recorded by others include FREAKIN' AT THE FREAKER'S BALL [Columbia] (1972), SLOPPY SECONDS [Columbia] (1972), DR. HOOK [Columbia] (1972) and BOBBY BARE SINGS LULLABYS, LEGENDS AND LIES (THE SONGS OF SHEL SILVERSTEIN) [RCA Victor] (1973).
Albums of original motion picture scores include Ned Kelly [United Artists] (1970), Who Is Harry Kellerman And Why Is He Saying Those Terrible Things About Me? [Columbia] (1971), in which Silverstein even played a role, Thieves (1977) and Postcards from the Edge (1996). Other recordings include Drain My Brain [Cadet] (), Dirty Feet [Hollis Music] (196, Shel Silverstein (Songs And Stories) [Casablanca] (197 and The Great Conch Train Robbery [] (1980).
"One's On The Way" is the biggest surprise to me on this list.