"I.O.I.O." has one of the stranger histories of any song by the Bee Gees, in terms of both its origins and evolution as a recording, as well as the shape that it finally took in the recording studio. For starters, it marked the group's first conscious delving into what is now called "world music" -- according to Robin Gibb, it grew out of his brother Barry's visit to Africa, and first appeared in 1968 on a rehearsal tape from the early part of the sessions for what became the Idea album. The song was put aside and wouldn't get finished until two albums later, following the split of the sibling trio, when Barry and Maurice Gibb -- working as the Bee Gees duo -- completed it at a small studio in Marble Arch during October of 1969. It was released as a single in March of 1970, and was also one of the highlights of the Cucumber Castle album.
The record, which Maurice Gibb claimed was never finished properly -- and still featured Barry Gibb's guide vocal in place of a finished performance -- was one of the most unusual in the group's history. Opening with a flourish of distinctly African-sounding drums, the chorus overdubbed by Maurice Gibb -- in the most prominent placement of his voice on a Bee Gees single A-side -- comes in followed by the acoustic guitar, and Bary Gibb's stunning lead lets the lyrics and the luscious melody flow out in leisurely, low-key fashion. The title chorus provides a break, followed by the second verse, telling of a lost love, and the chorus again provides a break -- Maurice Gibb's overdubbed vocals swell out, with Barry Gibb's gentle "I sing" leading them, for a slow faded amid some falsetto vocal gymnastics.
The song was released as a single by the duo version of the Bee Gees but, as with everything else from that hiatus period, was shunted aside when the three brothers began working together again. It was a cult favorite of fans, however, and made it onto The Best of the Bee Gees, Vol. 2 following their comeback with "Lonely Days", and seemed to impress anyone who heard it. In June of 1995, it was recorded with revised lyrics by the Dutch pop duo of Ronal & Peter in Holland, becoming a hit there and getting adopted as a chant sung by supporters of Ajax, a championship-level Dutch football team. Still more recently, it was covered by the Bee Gees-influenced trio B3.