John O'Dreams although often called a traditional Irish song, was written by Bill Caddick, using a tune by Tchaikovsky. The titular central character is equivalent to the Sandman, a fictional character who sends people to sleep. The song portrays all people as being "equal in sleep":
In this context, sleep may also be considered a metaphor for death, both as an eventual equalizer of all things, and for the allusion to a "crossing over," as in a river, a prevalent theme in Western spiritual beliefs.
The most popular arrangements are by English singer/songwriter Bill Caddick. Singers Gordon Bok, Christy Moore, Jean Redpath, Garnet Rogers and The Clancy Brothers with Robbie O'Connell also recorded versions. The enchanting arpeggiated melody is based on Tchaikovsky's Symphony No. 6, "The Pathetique", and is thought to have originated in either a Russian or Italian folksong.