Beginning GIMP: From Novice to Professional (Expert's Voice in Open Source)
From the reviews:"Peck’s textbook provides a thorough treatment of topics ranging from installation (on various platforms) and background on common graphic file formats, to drawing, photograph manipulation, filters/effects, and even scripting … . In addition, a thorough treatment of the tools useful to experienced designers is provided … . Peck’s book is effective in showing just how far GIMP has progressed in 12 years. Beginners may be surprised … with this free application, especially with the assistance of this clear, concise, and attractive textbook." (Ian van der Linde, ACM Computing Reviews, Vol. 49 (2), February, 2008)