This is basically the textbook on how to do TPRS. It is called the green book in many circles because it is the color green. Not much needs to be said about this book. It is a must have and full of so much vital information that it is an excellent resource.
As of 2008, there have been 5 editions. With this book, it is important to get the new editions because TPRS has changed so much over the years. It continues to evolve as it spreads and new helpful information continues to be established.
Definitely take a look at this! I look at it almost every day.