The Librarian

The Librarian of Unseen University was transformed into an orangutan as a side effect of a powerful magic spell. Discovering that being an orangutan has certain advantages for a librarian (such as not requiring a ladder to reach those tricky high-up shelves), he refused to be transformed back into a human, and has remained an orangutan ever since.

He retained his position as Librarian despite his condition because "he's the only one who knows where all the books are". The other wizards have gradually become used to the situation, to the extent that "if someone ever reported that there was an orangutan in the Library, the wizards would probably go and ask the Librarian if he'd seen it".The Librarian is known for his violent reaction whenever he hears anyone refer to him as a "monkey" (orangutans are apes).

The Librarian's actual name is mostly unknown; he is always simply "The Librarian". If the Librarian's true name were known, he could be changed back into a human, and he has carefully excised his name from the records of the University (since he has special access). It is thought, however, that he may once have been Dr. Horace Worblehat, which goes a long way to explaining why he's happier as an orangutan than as a human.

The Librarian served a brief stint in the city watch during the reign of terror caused by the dragon of Ankh-Morpork, where he helped to rescue Sam Vimes from the Patrician's cell. He retained an honorary position with the Watch, and is considered to be one of the first members of the 'Specials' - the Ankh-Morpork City Militia.

The Librarian has used his Librarianic ability of travelling through L-Space (the extradimensional space that connects all libraries and other large accumulations of books) to save books from the great library of Ephebe.

The Librarian once joined the Band with Rocks In since his large hands and wide reach make him an excellent organ player.