Don't Stop the Carnival by Herman Wouk — A comic novel about a New York press agent who abandons his career to buy a small hotel on a fictional Caribbean island. Wouk lived in the Virgin Islands while writing it, and the setting, the characters, and the particular chaos of Caribbean island life all ring very true. Essential reading before or after a visit to the USVI.
Omeros by Derek Walcott — The Nobel laureate's epic poem retells the Homeric cycle through the lives of Caribbean fishermen on St. Lucia. It is dense and demanding but rewards the effort, and it captures something essential about the Caribbean's layered history of colonialism, slavery, and survival that no travel guide can match.
A Caribbean Mystery by Agatha Christie — Miss Marple on a fictional Caribbean island; lightweight but enjoyable, and Christie's observations about the colonial world she was writing about are sharper than they first appear.
The Sugar Barons by Matthew Parker — A serious history of the rise and fall of the British sugar empire in the Caribbean. The Danish Virgin Islands were part of the same brutal system, and Parker's account of plantation society and the slave trade provides important context for the ruins visible throughout St. John.