The Chair of Indefinite Studies is a position within the Unseen University Faculty held by a high level mage (traditionally only Eighth Level Wizards are Heads of Department, but this seems to have lapsed under Archchancellor Mustrum Ridcully). The current incumbent seems to wander in and out of importance as part of the Faculty. For example, he goes to the lost continent of XXXX and accompanies the rest of the Heads of Wizardry on the mission to stop Cohen the Barbarian and his Silver Horde from inadvertently destroying the world by taking fire back to Dunmanifestin, the home of the gods, but he is not present at other trans-dimensional emergencies. Perhaps this is due to his insistence that once a problem becomes a 'definite' problem, it no longer falls under his remit as Chair of Indefinite Studies.
In Moving Pictures, the Chair is described as a white-haired old man wholly in keeping with the university ethos of very large meals six times a day. The combination of untended beard and the cumulative effect of those six meals a day combine to liken him, or the then post-holder, to an overstuffed horsehair armchair which is beginning to leak its stuffing along bursting critical seams. He attends the screening of Blown Away with the other covert wizards and, while he does think to suggest that his colleagues sneak into the Odium via the rear, he wholly fails to deliver any practical advice or assistance in the inter-dimensional leak that follows. In 'Hogfather', the Chair uncovered references to "lares and penates" in Woddeley's Basic Gods.
In The Last Continent, it's revealed that the Chair is fond of croquet and bridge. He also collects pressed lizards, a curious hobby he shares with at least one irritating young boy from 'Hogfather'. He wears expensive socks with flax-enforced heels. A staid, prim fellow, the Chair was the last of the faculty to develop an affection for Mrs. Whitlow in The Last Continent. Frequently a bit slow on the uptake, he admits that the state of magical research has passed him by in recent years, ever since dribbly candles fell out of favor. He was quite a drinker in his student days, having nipped over the University wall for a pint or three most evenings, like many students before and since. A likely contemporary of Ridcully and the Dean of Pentacles, as he remembers the latter being too studious to join in such forays.
He plays a minor, but important, role in Making Money, in re-introducing Adora Belle Dearheart to the Cabinet of Curiosity, and afterwards facilitating an introduction to Ponder Stibbons and the Department of Post-Mortem Communications.