Biological control agents can substitute hazardous pesticides and provide environmentally safe and sustainable control of pests, diseases and weeds. Often, exaggerating registration requirements prevent or delay market introduction of micro-organisms, semiochemicals and botanicals. This book is the result of the Europe-wide, two-year policy support action REBECA, a forum for representatives of academia, regulation authorities and biocontrol industry to discuss improved regulation rules. It provides a comprehensive review on existing data requirements and registration procedures. Risks and benefits of biocontrol in relation to trade-off effects resulting from unbalanced regulation are discussed. As a result, proposals for innovative and balanced regulation procedures are presented including recommendations how to accelerate the authorisation process. Considering concerns about possible non-target effects of beneficial insects, mites and nematodes this book proposes harmonisation of regulation rules and provides comprehensive material on the data requirements for authorisation, including guidelines for completion of possible application forms for macro-organisms. This book is a valuable source on state-of-the-art registration practice and possible policy steps to promote further introduction of biocontrol in agriculture practice.