The Last Continent by Terry Pratchett.
This book follows the "adventures" (or rather "attempts to not get killed") of inept Wizzard Rincewind on the strange continent of Fourecks (XXXX), which bears a stiking resemblance to Australia. Linked into this is is the attempt by the wizards of the Unseen University to find Rincewind, as only he knows the librarian's real name, needed to cure him of of a form of flu that has him changing into random items (all with a tell-tale covering of red fur). In typical wizard style they do this by going about things completely the wrong way, and putting the whole continent into danger.
This was Pratchett on fine form. I don't normally like books where Rincewind is a main character, as I find him annoying, but I got into this one easily and it kept me hooked. It was also fun seeing how many Australian references Pratchett can shoehorn into one book. Still, no worries, eh? ;)