It has been a century since the death of Élie Metchnikoff, who championed the role of phagocytosis in cellular immunity. Whereas others had observed the uptake of particles by cells from simple to complex organisms, he grasped its significance in the host response to injury and infection and established a firm basis for our understanding of inflammation and tissue homeostasis. The past century has brought improved tools of cellular and molecular biology to the study of phagocytosis and its contribution to physiological and pathological processes, including receptor function in innate and acquired immunity. In this review, I assess our present knowledge and consider opportunities for future research and therapeutic targeting.