Kraken

A forty-foot giant squid vanishes overnight from London's Natural History Museum, tank and all. Nobody can explain how something that size leaves a building unseen. Billy Harrow, the museum employee who prepared the specimen, is the one person who knows it well enough to be useful.

He soon learns that many people want the squid back. Rival squid-worshipping cults are after it, and so is a secret police unit that handles sect-related crime. The dead criminals of a magical underworld have their own claim.

Billy is pulled into a London he never knew existed, where belief acts as a physical force. Soon a corpse is found folded inside a glass bottle, and the city's familiars start attacking. The end of the world may be only days away.

This is urban fantasy with a dark comic tone, and the strangeness comes thick and early. The novel won the 2011 Locus Award for Best Fantasy Novel. Billy has to work out who took the squid and why, with the city's hidden factions closing in on him.