Our brain continuously decodes the complex visual scenes unwinding in front of us: both the nature of material entities, such as individuals and objects, and their immaterial interactions. I will briefly talk about individual recognition in monkeys and next turn to interaction processing. Interactions are fundamental in that they reveal hidden properties of intentional agents, such as their thoughts and feelings and of objects, such as their mass or material. Where and how interaction analyses are implemented in the brain is unknown. Using whole-brain functional magnetic resonance imaging in macaque monkeys, we discovered a network centered in the medial and ventrolateral prefrontal cortex that is exclusively engaged in social interaction analysis. Two additional networks, a parieto-premotor and a temporal one, exhibited both social and physical interaction preference, which, in the temporal lobe, mapped onto a fine-grain pattern of object, body, and face selectivity. Extent and location of a dedicated system for social interaction analysis in monkeys suggest that this function is an evolutionary forerunner of human mind-reading capabilities.