The first part of the theme is played twice and is completely made of notes from the major pentatonic scale of the first degree.
The tune is in the key of B-flat major and has a 20-bar structure with four distinct sections. The chord progression is mainly made of dominant-seventh chords on the first, fourth and fifth degrees, giving the song a bluesy feeling although it does not follow a typical blues progression. The subdominant (IV) chord in the beginning section emphasizes this bluesy feeling. In the second section, the tonic chord alternates with a second-inversion subdominant chord, creating a parallel to the I-IV-V progression (in which the tonic moves to the subdominant).
Marlena Shaw cover
Marlena Shaw recorded a version which peaked at no. 58 on the Billboard Hot 100 on the week of April 1, 1967.[4][5] It also peaked at no. 66 on the Cash Box Top 100 Singles chart on the week ending April 8.[6][7]
"Mercy, Mercy, Mercy" has been re-recorded numerous times, most notably by The Buckinghams, who reached #5 in August 1967, adding lyrics to the tune. Musicians on the Buckinghams' version included James Henderson, Lew McCreary and Richard Leith on trombone, Bill Peterson, Bud Childers on trumpet, John Johnson on sax, Lincoln Mayorga on Wurlitzer electric piano, Dennis Budimir on guitar, Carol Kaye on bass, and John Guerin on drums.[citation needed]
^"This album gave birth to a Top Ten single of the title tune, much to the astonishment of many..." Michael Cuscuna 1995 Capitol Reissue CD liner notes
^Whitburn, Joel (2004). Top R&B/Hip-Hop Singles: 1942-2004. Record Research. p. 24.
