The 4th Edition of the Blender Basics Book is now available on the Central Dauphin School District website as a free download. This edition has been completely revamped to match the 2.5 series with expanded chapters and activities. The book is available to download as an entire book or individual chapters. In addition to the book, I've started to create videos to go with the chapters (link on the website).
Also, with several request over the years for a printed version of the book, I now have an economical printed version available through Cafe Press , but you can still print and use the downloadable version as you wish.
Blender Basics is 178 pages, 23 chapters and designed to get new users up and running with "the basics" in as little as 30 hours.