Gestures are movements of our hands and arms that do not lead to a direct physical change in the world but that can directly change our minds. Recent theoretical advances and findings in cognitive science suggest that these body movements can play a wide role on cognition. This article provides a review on the role of gestures produced or observed, specifically as regards their role in communication, reasoning and learning. We'll try to outline how gestures can be considered both the result of cognitive processes and a critical component able to affect our cognition. We conclude with some evidences on the mechanisms underlying the beneficial effect of gestures on memory, and a brief discussion in the more general debate on the philosophical thesis of «extended mind».