Welcome to the Pathfinder Roleplaying Game. The Pathfinder RPG is an evolution of the 3.5 rules set of the world's most popular roleplaying game, designed using feedback from you and your group of dedicated gamers. Currently, you can download the Beta Playtest version of the entire rule set for free as a PDF from Paizo.
The Pathfinder Roleplaying Game launched in March of 2008 as a number of small Alpha documents. Since then, more than 45,000 gamers have downloaded the rules and posted up their feedback, resulting in the Beta Playtest Edition. The open playtest of these rules concluded on February 23rd, 2008, after almost six months of extensive testing and review. Over the next months, the rules will be refined into a finished game, to be released in August 2009. Look for previews of the finished game on our blog.
These rules are designed with backwards compatibility in mind. Meaning that if you already own a bookshelf full of 3.5 rulebooks, the Pathfinder RPG is designed to work with only a minimal amount of conversion. In fact, the Pathfinder RPG is designed to smooth over a number of the rough spots of the 3.5 rule set, making a number of existing books even easier to use. We are devoted to making the Pathfinder Roleplaying Game into the game that you want to play and we are excited to welcome you to the growing community of players, gamemasters, and designers involved with this massive project.
—Jason Bulmahn
Lead Designer
Paizo Publishing