1 Ontogeny of phagocytes.- 2 Phagocyte activation.- 3 Antimicrobial functions of neutrophils.- 4 Antimicrobial functions of macrophages.- 5 Immunologic functions of macrophages.- 6 Congenital and acquired neutrophil abnormalities.- 7 Interactions between antimicrobial agents and phagocytes.- 8 The role of phagocytes in non-infectious diseases.- 9 Cytokines: interactions with phagocytes and therapeutic potential.