Dr. Bartle's credits include inventing the things we're are talking about, and ... and ... hmmm. That's enough said, isn't it? But as it happens, he's also the source of the explorer-achiever-socializer-killer taxonomy of MUD players, and has written the new and authoritative textbook on Designing Virtual Worlds. Dr. Bartle - he's been going by 'Richard' around here - has a time perspective that is unmatched in the industry, and we are happy he's agreed to lend that perspective here. Welcome!