One of Infocom's biggest innovations was the Z-machine, the first commercial example of a type of program known as a "virtual machine." Virtual machines mediate between a program and a computer's operating system, so that the same program can run on different types of computers. Instead of having to retool all its games for each new model of computer, as other companies had to do at the time, Infocom just had to retool the Z-machine. Once that was done, Infocom's entire library became instantly available on that computer. The virtual machine was a key innovation: it's one of the reasons, for example, that online applications can run on any Web browser, on any operating system.

While Montfort says that it's hard to trace specific Infocom technologies back to particular MIT projects, he adds, "I don't think that somebody sitting in their garage unaffiliated with a university would have contrived the Infocom parser and the system for modeling a world." Like Spacewar, he says, Zork and later Infocom games were influenced by attitudes toward technology that have long been pervasive at the Institute. At MIT, says Montfort, "people are very accepting of exploration and playfulness with technology. It's okay to take a computer and create a game with it."

Through the Looking Glass

The player enters a stone building, slipping through its darkest shadows, and watching down dimly illuminated hallways for ­people who might detect his presence. The sound of his own footsteps loud in his ears, he listens for the softer footfalls that could warn him that someone approaches. "I'm sure I saw something," a cultured voice says, from off to the side.

The arrow strung on his bow prominent in his field of vision, the player continues to stalk. He picks off a few of the keep's denizens--often with an arrow to the back--before they can spot him. If they manage to spread the word about his presence, they are sure to overwhelm him, ending the mission.

Thief: The Dark Project advanced "first-person" gaming both technologically and conceptually when it was introduced in 1998 by Looking Glass Studios, a company full of MIT alumni that was originally based in Lexington, MA. A group including Doug Church '89 designed the game.

First-person games, often called FPSs (for first-person shooters), depict a world through the eyes of the character, an important change in perspective for game play: the player, like the character, can't see what might be behind her or around the corner. But until Thief came along, first-person games were typically about mowing down enemies wherever they could be found.