In the Mind of the Enemy — The Artificial Intelligence of Halo 2 describes the AI related techniques that have been incorporated into Halo 2, the new version of the popular xbox first person shooter game. (Not that we approve of games that encourage people to participate in mindless violence and aggressive behavior.) In this article, Chris Butcher, the software engineer responsible for making Halo’s agents more intelligent, describes some of the requirements and the techniques used to meet them. While there is not a lot of technical detail, the piece does a good job of motivating how game companies are using AI techniques. There is probably an even bigger role for intelligent characters in MMORPGs (massively multiplayer online role-playing games) like Middle-Earth Online. These games are much more about interactions among groups of players and artificial agents (mobiles). Moreover, the primary interactions are not always shooting, slashing and exploding. Given the way people are, I expect that interactive computer games will turn out to be one of the most important application areas for much of AI. Adding more AI to these games does involve scaling issues that are not present in PC or console games like Halo2. A successful MMORPG game uses a server farm to maintain a large and complex artificial world in which there may be on the order of ten thousand human players simultaneously interacting with an even larger collection of artificial agents.