So how did Donald Fagen end up playing on a couple of tracks on Clarence Fountain & Sam Butler's new album Stepping Up And Steeping Out?
The answer can be found in this short article from the huffingtonpost.com.
More on the album: http://www.fountain-butler.com
and on the MySpace page (including music).
P.S. The Gospel At Colonus mentioned in the article is out on CD and also on iTunes.