Beneficial Bacteria -- Plant-associated bacteria: survey, molecular phylogeny, genomics and recent advances -- Rhizobium-legume symbioses: molecular signals elaborated by rhizobia that are important for nodulati -- Nitrogen-fixing bacteria in non-legumes -- Epiphytic bacteria, their ecology and functions -- Bacterial endophytes: The endophytic niche, its occupants, and its utility -- Rhizosphere Bacteria -- Plant growth-promoting rhizobacteria -- Contribution of studies on suppressive soils to the identification of bacterial biocontrol agents and to the knowledge of their modes of action -- Root-associated bacteria inducing systemic resistance -- Rhizosphere competence and the role of root colonization in biocontrol -- Deleterious Rhizobacteria -- Plant Pathogenic Bacteria -- Agrobacterium biology and crown gall disease -- Clavibacter michiganensis, a group of gram-positive phytopathogenic bacteria -- The soft rot Erwinia -- Plant pathogenic Pseudomonas species -- Virulence functions of xanthomonads -- Plant pathogenic Ralstonia species -- Burkholderia -- Plant pathogenic members of the genera Acidovorax and Herbaspirillum. This volume is developed on the broad theme of plant-associated bacteria. It is envisioned as a resource volume for researchers working with beneficial and harmful groups of bacteria associated with crop plants. The book is divided into two parts. Part I (9 chapters) on beneficial bacteria includes chapters on symbiotic nitrogen fixers, diazotrophs, epiphytes, endophytes and rhizosphere bacteria and deleterious rhizobacteria. Part II (8 chapters) consists of detailed descriptions of 8 genera of plant pathogenic bacteria: Agrobacterium, Clavibacter, soft-rot Erwinia, Pseudomonas, Xanthomonas, Ralstonia, Burkholderia and Acidovorax & Herbaspirillum. There is an opening chapter on the plant-associated bacteria survey, molecular phylogeny, genomics and recent advances. And each chapter includes terminology/definitions, molecular phylogeny, methods that can be used (both traditional and latest molecular tools) and applications.