The thesis examin~ rural development in Tanzania from the precolonial period to~present time. The work is a historical study. It is shown that the pre-colonial rural economies were prosperous in crops and animals. Disruption and decline of these economies commenced towards the end of the last century. Depopulation, war and disease contributed to the decline. Colonial agricultural, trading and trades licensing policies are shown to have contributed to the process of creating rural backwardness. Rural backwardness manifests itself basically as rural poverty. Colonial marketing policies which helped to marginalize the peasant economy are analysed. A description of land alienation policies and their consequences on the rural economy is made. Measures by the authorities to stimulate rapid economic change in rural areas by bypassing the peasants are investigated. The crisis of large scale mechanized farming is outlined. Attempts by the policy makers and planners to rediscover the peasant in the transformation approach to rural planning are examined. The attempts by the peasants to organize themselves to promote rural development and the problems associated with this organization are critically explored in relationship to the policy maker~ attempts to control and patronize the peasant economy. Government policies and plans including grand plans aimed at the peasant to bring rapid economic and social development in the countryside are critically evaluated. The level of development of the peasant economy is elaborated empirically. The theory is advanced that the backwardness of the peasant economy is a result of bad policies and plans and exploitation and misunderstanding of the peasant by other agencies like the state and marketing institutions. The family farm is investigated in comparison to the large scale mechanized state farm. The superiority of the family farm in organization and capacity to survive harsh market and technical conditions and to create jobs is demonstrated. A theory on peasant farming in Tanzania is constructed and a theory on the causes of rural backwardness is tested. The nature of the Tanzanian state and its relevance to rural development are investigated. The failure by the state to formulate and execute sound policies and plans on rural development is demonstrated. The conclusion is reached that in rural development the work of actual production at the farm level should be left to the peasant himself because he can do the job best and at lower costs and that the government should only concern itself with improving rural transport and marketing.