The Nyakyusa of south-western Tanzania have received very substantial ethnographic coverage. Nonetheless there remain certain gaps in our knowledge of this society. The field-work by Dr. Godfrey Wilson and Professor Monica Wilson was done largely in the mid 1930s before structural-functional analysis had achieved its present refinement and was evidently influenced by Malinowski who was not himself known for a concern in sociological analysis per se. In these studies of the Nyakyusa, values, beliefs, and ritual were a main object of attention; they present Nyakyusa society as though it were a direct result of the Nyakyusa value system, although the actual workings of the society have been left rather obscure. It is presented as coherent, values and social organization reinforcing each other at every point. But internal evidence contradicts this picture, and on a priori grounds it may also be seen that there were several structural pressures towards incoherence, or rather, conflict between the actual development of social organization through time and those presumably timeless values reputed to maintain it.