7. Changing Planes, by Ursula Le Guin

This is a book of ideas. Elegantly written, subtle, philosophical and satirical, it uses fantastical worlds to provoke questions about how we live in our world. It begins with a woman who while waiting for a aeroplane discovers the technique for travelling to other planes (not aeroplanes, but planes of existence). Each plane is richly imagined and deftly described, but rather than depend on the sheer novelty and originality of the fantasy worlds, each story focusses on a distinct characteristic of an alien culture to reveal something about our own world, our human flaws and our potential. I loved it! Especially The Fliers of Gyr (if you've ever wondered what it would be like to be able to fly, read this), and The Seasons of the Ansarac (about a culture that travels seasonally between the country and the city - in the country they mate and have children, while in the cities the family splits up and they live in unrelated groups) . They're short stories, but so full of ideas and questions that they kept me entertained long after I'd put the book down.