SummaryPhagocytosis is defined as the receptor-mediated engulfment of large (≥0.5 μm) particles into plasma membrane-derived vacuoles called phagosomes. Following scission from the plasma membrane, the phagosomes undergo a maturation process, sequentially fusing with endosomes and lysosomes, ultimately becoming phagolysosomes — highly acidic and hydrolase-rich organelles that degrade the internalized particles. This brief description is a gross oversimplification of a highly complex and precisely choreographed process. Indeed, phagosome formation and maturation have emerged as paradigms to investigate many key questions in cell biology, including signal transduction, cytoskeletal remodeling, membrane dynamics and trafficking, and even gene expression.