Biological control (or Biocontrol) is the use of natural enemies (predators, parasitoids or pathogens) for the control of pests in crops. In classical biological control, a natural enemy is introduced as a new predator to a range where it is not native. In augmentative biological control, a large number of natural enemies are introduced, either in an area with no natural enemies like glasshouses, or to augment natural populations, to ensure a rapid pest suppression. In conservation biological control, habitats surrounding and within crops are managed to favour an increase in natural enemy populations while suppressing pest populations. These agroecological systems can be complex, and are affected by climate change, both negatively and positively. The object of this book is to synthesize and summarize current knowledge of the many ways climate change can influence the effectiveness of biological control systems. The book introduces the reader to general concepts and then describes climate change effects on the large diversity of macro- and microorganisms involved in biocontrol, and the possible increase or decrease in pest outbreaks following changes in characteristics (morphology, physiology, behaviour....), distribution or phenology. It then outlines methods for mitigating the effects of climate change through the adaptation of biological control strategies, including integrated pest management case studies from diverse continents and cultural contexts. Finally, it explores the economic and societal impacts of climate change on biological control systems. This is the second book in the CABI Ecostacking Series. Biological control is a major component of the ecostacking approach to cropping systems. It is intended for students, researchers, lecturers, and stakeholders engaged in biological control worldwide. It is also essential reading for research personnel and managers in companies that produce biological control agents for field application.