52:1 The children of the Lamp: The Eye of the Forest, P. B. Kerr.

The whole children of the lamp series is a good, fun read. In this book, so much happens, it's hard to pick what to put up here. Well, put simply, 2 sets of twins go to the Eye of the Forest. Mr. Gaunt gets kidnapped, and Mr. Rakshas is sort of still alive. Hard to explain, but the whole series is really great.