This thesis examines seringais (rubber estates) on the Brazilian Amazon from the perspective of capitalist social relations of production in the period from the 1870 to 1930. It is divided into four parts. The first part introduces the subject. The second part considers the social relations of land property and the selective way of privatising land to argue that seringal is private property and that there was a free labour market. The third part discusses the engagement and the forms of controlling and disciplining labour. The fourth part focuses on profitability and capital accumulation by demonstrating that (a) the local investors had their own project of economic political changes, (b) this and a converging view on the use of natural resources constitute decisive elements in their decisions of re-investments. Rubber enterprises were usually run as partnerships and they invested mainly in the production of the Fina Hard Para kind, which was considered the best quality and commanded the highest price at that time, and in the diversification of economic activities. As this thesis demonstrates, the social relations of production in seringal are capitalist due to the following features: (a) they are organised to produce commodities for profit in order to ensure capital accumulation; (b) they are characterised by the command of capitalists over subordinated forms of free labour; (c) this command is based on the private ownership of the main means of rubber production. The specific features of the relations of production in seringais are basically twofold: (a) the employment of different forms of subordinate free labour, including waged and salaried, in which seringueiros (rubber tappers paid by results instead of by work time) were predominant and (b) the geomercantile privatisation and use of natural resources, involving a converging interaction with nature.