This book focuses specifically on games I have worked on, from LegendMUD up through social games, and is a book of design history, lessons learned, and anecdotes.
There’s still nowhere near enough material out there in print covering things like the history and evolution of online worlds (MUDs especially), in-depth dives into decisions made in games by the people who made them, and detailed breakdowns of how they worked.
* MUDs, which has design articles about DikuMUDs, design and administrative practices material on LegendMUD, a lengthy article on the struggles with MUD governance that we went through back then, and even samples from what MUDding was like (for the younger folks out there! ).
Star Wars Galaxies, including the whole postmortem series, a new overall design overview, and even materials I wrote to the players explaining our design philosophy.