Book excerpt: Provides fundamental knowledge every plant scientist and student of plant pathology should know, including important historical events that gave birth to the field as well as its recent advances. Illustrates the symptoms caused by bacteria in a way that facilitates comprehension of the many different types of plant diseases that they cause. Each symptom type is presented with a detailed example of a causal agent and its characteristics, diagnostics, and mechanisms of virulence and pathogenicity. Also includes an extended discussion on the molecular mechanisms of virulence and a chapter on epidemiology and disease control.