A History of Methodological, Theoretical and Empirical Approaches to Biological Control.- Classical Arthropod Biological Control: Measuring Success, Step By Step.- Success in Biological Control of Arthropods by Augmentation of Natural Enemies.- Success in Conservation Biological Control of Arthropods.- Success in Biological Control of Terrestrial Molluscs.- Success in Biological Control of Aquatic Weeds by Arthropods.- Success in Biological Control of Terrestrial Weeds by Arthropods.- Success in Biological Control of Plant Pathogens and Nematodes by Microorganisms.- Success in Biological Control of Soil-dwelling Insects by Pathogens and Nematodes.- Success in Biological Control of Above-ground Insects by Pathogens.- Success in Biological Control of Weeds by Pathogens, Including Bioherbicides.- Success in Biological Control of Vertebrate Pests.- Non-target Effects of Biological Control Agents.- Synthesis: The Future Success of Biological Control.