Book excerpt: Lewis Carroll the author of the world famous Alice in Wonderland is well known even today for his fiction, but his tenure as professor of mathematics at Oxford university is less well known as is his love of logic problems. Carroll was a mathematician at heart; he deeply loved and was fascinated by the subject. At first it may seem odd that a creator of such nonsensical writings would have such an interest in this area, although the logic involved in maths appealed to the very clever mind of Dodgson, and logical oddities are at the root of a lot of the wit in the Alice books.