The entire Pro Git book, written by Scott Chacon and Ben Straub and published by Apress, is available here. All content is licensed under the Creative Commons Attribution Non Commercial Share Alike 3.0 license. Print versions of the book are available on Amazon.com.

This is a fantastic book about Robot competitions and how important the skills learned by the kids are valuable throughout life and to the future of our country. I highly recommend it to everyone interested in robots, education and building a strong country.