Book excerpt: This book aims to address the importance of natural enemies and functional diversity for biological control in Neotropical agroecosystems. Several aspects related to the conservation of natural enemies, such as vegetation design and climate change, are discussed in Part 1 and the bioecology of several insects groups used in biological control in Latin America is presented in Part 2. Part 3 is devoted to mass production of natural enemies while Part 4 describes how these insects have been used to control of pests in major crops, forests, pasture, weeds and plant diseases. Lastly, Part 5 reports Latin-American experiences of integration of biological in pest management programs.