Boards of Canada's Peel Session is a recording of their 21 July 1998 broadcast on BBC Radio 1 for wikipedia:John Peel's radio program. It features significantly different takes of both Aquarius and Olson. The version of Happy Cycling that we see on this release is not the same as what was actually broadcast, here we find the polished version that also appears as an extra track on Music Has The Right To Children and the broadcast version formerly known as Bad Day being dropped.
There is a great deal of misunderstanding about the nature and timing of this recording, in part because of the surfacing of an unreleased track on peer-to-peer networks entitled "XYZ." This track appears to have been a part of the Peel Session but was strangely omitted from the track listing of the official release. "XYZ" in its full 9:38 cut (shortened versions still circulate) includes an exchange both before and after the track between John Peel and Boards of Canada.
Peel Sessions normally consisted of four tracks which were recorded in advance in the BBC recording studio and broadcast at a later date when the band were not present. Sometimes bands played live on the programme, but they were not referred to as Peel Sessions. The BoC session was unusual because they were in the BBC recording studio recording their session at the same time as the Peel programme was on air. This meant that they could have a live link-up with BoC in the recording studio, and that's when the interview took place. They played XYZ live on the programme at that time (16-6-98 ), but that was the only track they played and the mp3 of XYZ with the interview really is the whole thing. The complete Peel Session was broadcast on 21-7-98 with all 4 tracks, but the band were not present and there was no interview.