Captains of the sands"" are African overseers who sold their own people into 18th-century slavery--and the narrator of this gritty picaresque adventure soon finds himself among them. He is English Tom Derker, who's orphaned when his farmer-parents die during the snowbound winter of 1749. So, eagerly falling in with his charismatic Uncle William, a slaver sea-captain, Tom finds himself sailing the Liverpool/West Indies trade triangle--featuring a grim form of slave-trade on the Ivory Coast (bartering for one or two at a time, with many dying before Uncle William gets a full cargo). Then William and Tom are taken captive, lodging with the kind Jola tribe until they are ransomed: Tom falls in love with native gill Fourfarthings before he sets sail again. And when, months later, a group of Jolas is sold to William, Fourfarthings is among them. So Tom's attitude towards the slave-trade begins changing--especially when a beloved alcoholic officer is shot while attempting to free the slaves. And he buys Fourfarthings in the Indies. But Tom's dream of their life together in England is dashed when Uncle William takes Fourfarthings as his own willing mistress and informs Tom of his true parentage: Tom deserts, becomes pot-boy in a whorehouse, joins the decadent Antigua high-life, eventually kills William, and takes off to try his fortune in the American colonies. Finally, then, back in England, active in the Anti-Slavery Society but still involved in profitable injustices, Tom assesses his seven years in the slave trade and admits never having had ""one true and equal relationship with a black person, man or woman, and now it was too late, because I knew too much, and they would always shut me out."" A bit preachy, perhaps, in its moral lessons--but a taut, dramatic adventure that reworks the old conventions with a strong, grimy sense of raw atmosphere and ugly realities.