If you find this interesting, you will love his book "Designing Virtual Worlds". The first chapter covers the types of players in much greater detail. Its a fantastic book and I enjoyed reading it. Richard Bartle does a great job of explaining his points and backing everything up with references, so even if you don't agree with some of his observations, you can see why he thinks so and perhaps learn from it. Definitely a must read if you're developing a MUD or MMO game, but a good read even if you're not. </advertisement>