Besides linguistic communication, which is at the core of human communication, humans communicate using arm gestures, body postures, facial expressions, eye contact, and head and body movements. Communication may be intentional or non-intentional. It is very plausible that intentional communication is an evolutionarily late development of non-intentional communication. In the motor cortex of the macaque monkey, it was discovered that there is a particular set of neurons that discharge both when the monkey observes a given motor act and when it does the same act. These neurons, called “mirror neurons,” represent a system that directly matches observed and executed actions. This article first provides an overview of the mirror neuron system in monkeys and then looks at its role in intention recognition. It also considers neurophysiological evidence of the mirror system in humans and discusses brain imaging studies of the human mirror system, the link between mirror neurons and language, the transition from gestures to sound, and the appearance of echo-mirror neurons.