Trade wind

The scene is teeming Zanzibar just before the American Civil War, when the Isle of Cloves was a center of African slave trade. To it comes Hero Athena Hollis, a Boston bluestocking filled with self-righteousness and bent on good deeds.
Then she meets Rory Frost, a cynical, wicked, shrewd and good-humored trader in slaves. What is Hero to make of him (and of her feelings for him)?

"Tightly plotted, crammed with detail and irresistibly romantic." (Cosmopolitan)

Note: M.M. Kaye is the author of The Far Pavilions, one of the great stories to emerge from British India.