West African societies were transformed by the slave trade, even in regions where few slaves were exported. While many books have been written on the import and export trade and on warrior predation, Dr Searing's concern is with the effects of the Atlantic slave trade on the societies of the Senegal river valley in the eighteenth century. He shows that the growth of the Atlantic trade stimulated the development of slavery within West Africa. Slaves worked as seamen in the river and coasting trades, produced surplus grain to feed slaves in transit, and sometimes came to hold pivotal positions in the political structure of the coastal kingdoms of Senegambia. This local slave system had far-reaching consequences, leading to religious protest and slave rebellions. The changes in agricultural production fostered an ecological crisis.