A key theme in the West African trading system of the nineteenth century is the transition from the slave trade to 'legitimate' commerce, and its significance for the African societies of the region. In this period of transition, trade in palm oil was at the core of relations between Britain and West Africa, and of immense importance to the economies of large parts of West Africa. Martin Lynn's authoritative and comprehensive study of the palm oil trade covers the whole of this critical period for all of West Africa. It explains how the palm oil trade grew organically out of the organisation of the slave trade. The situation changed sharply with the development of steam communication between Britain and West Africa from the 1850s, leading to severe problems for the commerce in the second half of the century, the erosion of African brokers' powers, and the restructuring of the trade thereafter. The result was a crisis within the trade towards the end of the century and, eventually, with the arrival of colonial rule, the ending of the long established structures of the commerce.