This volume provides a detailed review of research covering different modes of interaction between microbes and plants. Included among the interactions examined are: the symbiotic association of rhizobium, azorhizobium and frankia with different plant systems; disease resistance strategies for plants; the role of the agrobacterium system in the formation of tumours, and oligosaccharides produced as a result of the degradation of plant microbial extracellular matrix.