When my sister was 10 she bought a rather battered copy of a book called Marianne Dreams at our school summer fair. A few years later, when she decided it was too young for her, she handed it on to me. I love puzzles – not particularly the kind that have to be solved, like crosswords, but ones that intrigue in the same way as a complex painting or a spider’s web. Marianne Dreams, published in 1958, is that kind of novel. Its plot is driven by mysterious connections – invisible threads that join together people and things in worlds both real and imaginary – and while the story may be resolved at the end of the book, the puzzle remains.