Besman overdubbed two vocals by Hooker, one of the first times that technique had been used on record though it had been pioneered earlier by Les Paul.

[2] According to reviewer Richie Unterberger:The overdubs weren't entirely in sync either, creating what was then and still is an eerie effect, like that of a voice echoing around the inside of a water tower.

[1]As with Hooker's earlier hit, "Boogie Chillen'", Besman leased the recording to Modern Records in Los Angeles, and a co-writing credit (and, hence, a share of royalties) for "I'm in the Mood" was given to "Jules Taub", a pseudonym used by one of Modern's owners, Jules Bihari.

[3] The record entered the Billboard Rhythm and Blues chart in October 1951, spending four weeks in the number one position from November,[4] and reputedly selling a million copies.

[1] The song has been recorded by several other musicians including John Hammond Jr. (1967), Buddy Guy and Junior Wells (1981), and Jack Bruce and Gary Moore (2002).