Brazil once enjoyed a near monopoly in rubber when the commodity was gathered in the wild. By 1913, however, cultivated rubber in South-east Asia swept the Brazilian gathered product from the market. In this innovative study, Warren Dean demonstrates that environmental factors have played a key role in the many failed attempts to produce a significant rubber crop again in Brazil. In the Amazon attempts to shift to cultivated rubber failed repeatedly. Brazilian social and economic conditions have been blamed for these failures, in particular the failure of local capitalists and the refusal of the working class to accept wage labour. Dean shows in this study, however, that the difficulty was mainly ecological: the rubber tree in the wild lives in close association with a parasitic leaf fungus; when the tree was planted in close stands, the blight appeared in epidemic proportions.