Section 11: Sources.
These books have been helpful in the preparation of this FAQ. Any contibutions on books you may have found useful will be duly noted and appreciated.

Soul Music: Who's Who. Tee, Rick. Prima Publishing, Paperback. 1991
By far the best overall book I've seen on Soul Music, with interesting articles on most moderately obscure artists.

Rock Albums of the '70's, a Critical Guide. Christgau, Robert. Da Capo, Paperback. 1981
A good overview of the '70's, covers moderately obscure artists. Most useful if scrutinized for all its information, as it does not concentrate on soul/ funk etc. Mandatory if you need a handle on non-soul music as it has excellent coverage of rock, blues, and pop music of old.

Rolling Stone Album Guide. Edited by Anthony DeCurtis and James Henke with Holly George-Warren, Reviewed by Mark Coleman, J.D. Considine, Paul Evans, David McGee.
Good overview of all music, lacks coverage of obscure artists, most useful because it provides an overview of an artists entire career and contains warnings of what albums to avoid and advice on which to buy.