Blender is a free open source 3D content creation suite. The Essential Blender comes in as a reference book for it, which also features lots of the basics about computer animation (CA) and its different branches, such as modeling, animation, rigging, skinning, lighting, particles, compositing. Most chapters in the book are approached in a two-pronged fashion, starting with a hands-on section, walking the reader through the steps to implement a particular feature, followed by a discussion section.
The book is written in an easy-to-follow language, authored in great open source style: through the collaboration of multiple writers with an editor (Roland Hess) at the helm. It is structured in a progressive way, taking the uninitiated in the world of CA through a very well-thought step-by-step process. This makes it a very valuable resource for people who are learning about CA and even other platforms such as Maya. However, it may be repetitive to those with an education or a background in CA.
Perhaps the biggest shortcoming in The Essential Blender is the complete lack of color illustrations, which occasionally makes the visual examples unclear. Besides that, it's a great reference for those wanting to jump on this very popular 3D design tool: so much so, that it even includes a complete version of Blender 2.44 on a CD-ROM it comes with.