From the introduction:
Simpli-Six is a roleplaying game designed to be easy to learn, easy to play, and quick to set up and start. Contained within this book is everything that a small group of 3-5 people need to set up, build a character, design an adventure and have one (and hopefully more) evenings full of fun. This book includes both the basic rules for creating a basic starting character as well as the rules of the game, also known as the Game Mechanics, needed to play a game session or a campaign.
Although the rules can be used to play any setting or genre that the participants desire, a multi genre setting, Arkalanon, is included towards the back of the book along with several suggestions that potential GM's and players alike may build off of. As for the game itself, all that is needed to get started and play are this book and the following things.