Understanding the mechanisms by which plants tolerate attack by pathogens, herbivores, or endure abiotic stress is a crucial part of learning how to enhance plant productivity and crop yields in the face of dwindling global agricultural resources. This book deals with the ability of plants to tolerate such attacks and stresses, and examines in detail various aspects of resistance responses and mechanisms of resistance. The content of this book is designed to be useful to those already knowledgable in the fields of plant resistance mechanisms, and those interested in learning more about these phenomena. This book is suitable for upper-level undergraduate and graduate students, researchers, and those teaching upper-level undergraduate or graduate-level courses in plant physiology or plant pathology.