'The Book of GIMP' Leaves No Detail Behind
The Book of GIMP: A Complete Guide to Nearly Everything combines a step-by-step approach to learning how to use this epic graphic image manipulation program (hence the name "GIMP") with a handy reference manual supplemented with very useful appendices. Whether you are a GIMP beginner or a veteran user, this book will save you hours of trial and error when editing graphics files.
It is not the only useful instructional guide on navigating through the difficult photo editing app, but it is one of the most current options available. It focuses on the latest iteration of GIMP, version 2.8.
I've used GIMP for many years, often being forced to reach for a variety of self-help sources to complete a graphical editing task. The Book of GIMP, released this month, is an excellent teach-yourself alternative.