Baf's Guide to the IF Archive is a website that attempts to catalogue every game within the massive IF Archive. "Baf" is Carl Muckenhoupt. He created the guide in 1995 and continues to maintain and upgrade it. Over the years, Baf has been assisted by a small army of contributors; see the Credits page.
Visitors to Baf's Guide primarily search for a game by its title or its author. A game listing on Baf's Guide may include quite a bit of information about that game, including its genre(s), year of release, publisher, platform, features within the game (does it have a maze? just one-room? a female protagonist? offensive content?, etc.), which competition(s) it was in, sometimes a short review, and more.
However, the primary feature that every game listing has are links to the files within the IF Archive so you can download the games and play them.