I haven't read this book often, or in a while, but The Truth Shall Make Ye Fret podcast are covering it this month and I decided I wanted to keep up with the conversation so I got the audio book. I found this book really confusing when I first read it, maybe twenty years ago, and I am only marginally less confused. Not quite Bursar level confused, but confused enough. It doesn't have the subtlety of later Discworld books but is more sophisticated than the earlier books. The main plot is Rincewind has ended up in XXXX and meets a kangaroo who tells him he needs to break the drought. Meanwhile, the Librarian is ill and the Faculty of UU is desperate for a cure; the library has become dangerous without the Librarian to issue a sharp 'OOK' when the books misbehave. In their search for Rincewind, they end up trapped on Mono Island with the God of Evolution 30,000 years in the past.