The book “Brazilian foreign policy and Unasur: Geopolitics and expansion of Brazilian capitalism in South America” analyzes the tension between the political and economic dimension of Brazilian foreign policy in the first decade of the 21st century. Such tension is examined at the systemic level, involving the relationship between State and capitalism; at the regional level, between the political projects of regionalism and the expansion of Brazilian capitalism in South America, and at the national, domestic level, between the foreign policy guidelines of the different political coalitions and their models of economic development. The work highlights Brazil’s role in the creation of the Union of South American Nations (Unasur), the role of Brazilian companies in the region and the contradictions between the geopolitical conception of Brazilian diplomacy and the dynamics of the country’s private investments in the region.