It is very much the PhotoShop of the open source world.
The GIMP is a powerful image manipulation package, provided under a free software license. It is very much the PhotoShop of the open source world. This book is an excellent introduction and tutorial to The GIMP's many powerful features. It is not however (and is not intended to be) a user manual. There is a separate and complete user manual for The GIMP available elsewhere.
The book is available on-line, it is published under an open-source license - although cleverly they don't mention this in the paper copy itself. However useful it is to have the on-line copy, I cannot stress enough the quality and value in the paper copy of this book.
Each chapter covers a different theme including layers, selections, masks, colour spaces and blending, photo touchup and enhancement, compositing, rendering and web-based image production (including animated GIFs and imagemaps). The material is thoughtfully presented as a series of walkthrough examples.
The physical production of the book itself is very good. Every page is in full colour and each chapter's start has a colour flash at the edge of the page to allow you to easily locate it. The content has been equally well thought out. There is a very comprehensive index. At the end of each chapter is a list of FAQs - correcting common misunderstandings about the chapter's subject. All diagrams are very clearly produced.
My only gripe with the book is that there is no overview of the use of the standard toolbox of tools. I feel a simple explanation of how to use the various painting controls at the start of the book would have set the context for some of the later chapters. This deficiency reflects the focus of the book, the image manipulation facilities of The GIMP, which indeed is the main thrust of the package.
For more information on The GIMP seewww.gimp.org.