Who is Ponder Stibbons from The Last Continent: A Discworld Novel and what is their importance?

The youngest and keenest member of the faculty of Unseen University (UU) in Ankh-Morpork, Ponder is the inventor of Hex, the complex mechanism that transports Rincewind to the Counterweight Continent in the novel of Interesting Times. It then misdirects him to the last continent on Discworld, Fourecks, rather than home. Needing Rincewind's services to heal the ailing Librarian, the faculty in the present novel decides against using Hex again for safety's sake, but stumbles through time and space, eventually to meet up with Rincewind on Fourecks.