Title: Deep Secret
Author: Diana Wynne Jones
What it's about: Rupert Venables is a Magid, one of the magic-users who helps keep the universe running smoothly. He's really only a beginner, but when his mentor dies, it's up to Rupert to appoint a new Magid. To take care of this task, he decides to bring all his potential candidates together in one place, which happens to be a sci-fi/fantasy convention. It will be up to him to select the proper Magid while also dealing with a collapsing empire a couple worlds away.
What I thought: This book is a great example of the wonderful chaos that Diana Wynne Jones is so fond of instilling into her stories. Rupert and Maree are both fun characters, plenty flawed but still quite likeable. The portrayal of the convention is good; you can see some gentle mocking along with a respect for people who enjoy hobbies like that. It makes for a great setting, too. The way that magic is shown to work and the system of different worlds is a unique one.
Overall: This is one of my favorite books by Diana Wynne Jones and really one of my favorite books, period.