When I first saw this product i was under the impression I needed it to run Gamma World. This is not the case. The Players book is all you need to run Gamma World. This book is intended for Game Masters with little or no experience running a RPG. The information is not just useful for Gamma World but any RPG and should have been packaged as "How to be a GM" or "GMing for Dummies" it is very well writen and is a great resource for any starting GM. As a GM that has been running games since the first release of Gamma World (metamorphis Alpha in the late 70's), and every version of it since tehn, I founld little I did not already know. I have been GMing for about 25 years. For me I found it close to useless, but if you are new at this you could learn alot from this book.
[3 of 5 Stars!]