Rhodococcus are metabolically versatile actinobacteria frequently found in the environment with potential applications in bioremediation, biotransformations and biocatalysis, among other biotechnological processes. These microorganisms are currently the subject of research in many countries of the world. The number of publications and patents on rhodococci has intensified significantly within the last years. In this context, the knowledge acquired during the last decade about basic aspects of Rhodococcus biology is significant and promising about their future prospects. Several genomic projects of Rhodococcus members are now available and in progress through public and private efforts due to the increasing interest in their use for biotechnology. The large Rhodococcus genomes containing a multiplicity of catabolic genes, a high genetic redundancy of biosynthetic pathways and a sophisticated regulatory network reflect the complexity of Rhodococcus biology. The combination of functional genomics studies with biochemical and physiological knowledge is providing new insights, which will enable the biotechnological use of rhodococci. This Microbiology Monographs volume provides a thorough review of many aspects of biochemistry, physiology and genetics of Rhodococcus, in the context of new genomic information. Expert international scientists contributed with reviews on the extraordinary capability of Rhodococcus genus for biodegradation of diverse compounds and bioremediation, biosynthesis of lipids and biosurfactants, adaptation and tolerance to solvents, interaction with metals and biotechnological applications. Chapters dealing with taxonomy, genomes and plasmids, and oligotrophic and central metabolism are also included in this volume. Moreover, the book includes basic aspects of the phytopathogenic R. fascians.