QUOTE(confutatis @ Sep 2 2008, 07:04 PM)

The Cambridge Companion to the Organ has excellent articles on specific periods.
Does for the FRCO as well, an excellent book and scholarly too.
On the particular period you mention, there is FRANCOIS COUPERIN AND THE FRENCH CLASSICAL TRADITION by Mellers and The Language of the Classical French Organ: A Musical Tradition Before 1800 by Douglass Fenner. I think the second of these is thought to be the better of the two. (Sorry about the caps lock, not sure how that happenned!)