This paper explores the continuous role that science has played in the esta
blishment of a colonial and post-colonial "development regime" in Africa. E
xamining development schemes that flourished between 1930 and 1970, the pap
er shows how African agrarian societies became objects of both state interv
ention and expert knowledge. In pursuing large scale social engineering and
social experiments, these schemes constituted a particular-coionial?-way o
f managing the African environment and of crafting knowledge on African soc
ieties. In constructing development ideologies and practices in the late co
lonial and post independence periods, they also played an important part in
the construction of the African state. Their approaches shaped the future
of tropical medicine, agriculture, and development studies. Ironically, the
y also created the preconditions for later interest in the values of indige
nous knowledge.