Richard Bartle had a recent post about the pre-history of MMOs.
I’ve read so many histories of MMOs that are just plain wrong, that I myself always try to get it right to the best of my knowledge and understanding. This is why when people introduce me as “the man who invented online games” or whatever, I always mention that I co-invented them with Roy Trubshaw. If I’m able (which isn’t always possible in live interviews), I’ll also correct the focus (it’s just virtual worlds) and point out that plenty of other people independently invented them too: Roy and I did MUD; Kelton Flinn and John Taylor did Island of Kesmai; Randy Farmer and Chip Morningstar did Habitat; Bruce Maggs, Andrew Shapira and David Sides did Avatar; Rich Skrenta did Monster; Alan Kleitz and Bob Alberti did Sceptre of Goth.
He goes on to talk about the genealogy of games and the allocation of credit.
Worthy reading for folks who care about the world before the World of Wacraft.