The words to this song, along with the texts of "Saint Stephen" and "Alligator" got Robert Hunter invited to write lyrics for the Grateful Dead in 1967. He went on to be the band's primary lyricist for almost thirty years.
In A Box of Rain, his published collection of Dead lyrics, Hunter notes: "Nobody has ever asked me the meaning of this song. People seem to know exactly what I'm talking about. It's good that a few things in this world are clear to all of us."
Source: Hunter, Robert. A Box of Rain: Lyrics: 1965-1993 Penguin Books, 1990