Phagocytosis is a biological process in which specialized cells engulf and digest harmful particles, such as bacteria, viruses, and dead or damaged cells. This process plays a crucial role in the immune system, as it helps to protect the body from invading pathogens and clear out debris. Phagocytosis involves a series of steps, including recognition of the target, engulfment of the target by the cell membrane, and digestion of the target within specialized compartments called phagosomes. Researchers study phagocytosis to better understand how the immune system functions and to develop new treatments for diseases involving immune dysfunction.