Annual Plant Reviews, Volume 11 Plant diseases are destructive and threaten virtually any crop grown on a commercial scale. They are kept in check by plant breeding strategies that have introgressed disease resistance genes into many important crops, and by the deployment of costly control measures, such as antibiotics and fungicides. However, the capacity for the agents of plant disease - viruses, bacteria, fungi and oomycetes - to adapt to new conditions, overcoming disease resistance and becoming resistant to pesticides, is very great. For these reasons, understanding the biology of plant diseases is essential for the development of durable control strategies. This volume provides an overview of our current knowledge of plant-pathogen interactions and the establishment of plant disease, drawing together fundamental new information on plant infection mechanisms and host responses. The role of molecular signals, gene regulation and the physiology of pathogenic organisms are emphasised, but the role of the prevailing environment in the conditioning of disease is also discussed. This is a book for researchers and professionals in plant pathology, cell biology, molecular biology and genetics.