Beginning GIMP: From Novice to Professional (Expert's Voice in Open Source)
Beginning GIMP: From Novice to Professional (Beginning Series: Open Source)
GIMP 2 for Photographers: Image Editing with Open Source Software
The Artist's Guide to GIMP Effects: Creative Techniques for Photographers, Artists, and Designers
GIMP Pocket Reference
GIMP User's Manual
GIMP User's Manual: Learn the Ins and Outs of GIMP from the Masters Who Wrote the Official Manual on the Web