The MIT Science Fiction Society is usually referred to by its acronym MITSFS. It is a student group recognized by the MIT Association of Student Activities, a branch of the MIT student government. MITSFS maintains the world's largest open-shelf collection of science fiction.

The library is operated by students, alumni and MIT affiliates. Some of these people, called keyholders hold MITSFS open on a slightly erratic schedule that changes from term to term. When the Library is open, anyone is welcome to browse the circulating and non-circulating books and magazines provided that they leave any bags or backpack behind the front desks. In addition, some other materials are located in the special reserve section known as damnation ally.

Membership which is available for purchase on a term, year, life or permanent basis; permits the member to checkout up to 8 books from the circulating collection for up to three weeks. Books may be returned by checking them in in person, or attaching a note and sliding them through the door slot to the room the library is in. Failure to return the books results in loss of checkout privileges until you pay a fine and return the book or pay for the lost book to be replaced. Theoretically MITSFS is actually part of the official MIT Library system, and can block students from graduating if they owe a fine, but in practice, this does not happen.

In addition to the Library, MITSFS Publishes the Twilight Zine on an infrequent schedule. This zine contains art, stories and book reviews. There are also MITSFS meetings every week. These are on Friday starting at 5:30 or 6:30 pm depending on the season, and contain no real business and many in-jokes. These meetings are run by the MITSFS officers.

More information and current attempts at schedules can be found at