"Cassidy" is a song written by John Barlow and Bob Weir[1] and performed by the Grateful Dead, Ratdog, and Phil Lesh & Friends.
[2] The song appeared on Bob Weir's Ace, and the Grateful Dead's Reckoning and Without a Net albums.
[1] The lyrics also allude to Neal Cassady, who was associated with the Beats in the 1950s[4] and the Acid Test scene that spawned the Grateful Dead in the 1960s.
The song was first performed on March 23, 1974 at the Cow Palace in Daly City, California.
On the Ace studio album version, Donna Jean Godchaux joins Weir on vocals.