Although it's really been assumed all along, Valve has never confirmed that Half-Life 2 is actually in production. Valve still hasn't commented on it, but at the Entertainment for the Interactive Age conference, GameSpy Daily heard NYU Computing Science professor Ken Perlin say that he is currently working closely on some new technology with Valve that may be used for Half-Life 2. The technology he's working on will let players "fall in love" with the characters, and may or may not actually make it into the game, but the fact that he's talking with Valve at all about this means the game is at least in production.