Piranesi was none of the things I feared it might be -- it was fairly short, entertaining, engaging and original. It takes the form of a diary, of a young man who lives in a vast house, empty of everything but mysterious statues and the in-rushing sea, and the Other, whom he sees from time to time but who is busy on his own researches. The mystery of this young diarist's identity, the nature of the House and how he has ended up there, unfold in an intriguing speculative fiction that has magical and philosophical elements, but is ultimately grounded in the real world. As more visitors appear in the House (which seemingly stretches for kilometres in every direction, made up of immense Halls and Vestibules, and the odd abandoned skeleton), 'Piranesi' comes to question everything he has taken for granted, and his whole reality is turned upside down.
Piranesi is beautifully written and elegantly designed and I was sorry when my wander through its majestic, mysterious and chilly halls was over. I'm counting it as adult fiction, but it could be young adult, too. One of the best books I've read this year.