Legionellosis is a disease of significant medical and public interest. Legionella is commonly found in aquatic habitats where its ability to survive and to multiply within different protozoa equips the bacterium to be transmissible and pathogenic to humans. In addition, Legionella has become a favored model system to analyze the mechanisms of bacterial survival, acquisition of nutrients, and intracellular replication. Following the recent publication of the genome sequences of four L. pneumophila strains, it is now feasible to investigate the whole genome in silico, the transcriptome via micro arrays, and the proteome by two-dimensional gel electrophoresis. Research in the fields of clinical features, diagnosis, treatment, and epidemiology continues to generate new data. The topics covered by this volume range from the history of the identification of Legionella and clinical disease treatment, to the microbe's gene expression and secretion systems, as well as its strategies for intracellular multiplication and nutrient acquisition. The main focus of the book is the current state of many of the most critical features of Legionella. Internationally renowned authors have contributed chapters describing and discussing the latest research findings with an emphasis on molecular aspects. The editors and authors have produced an excellent book that will be an extremely useful reference source. This comprehensive publication is aimed at readers with teaching or research interests in microbiology, genetics, genomics, infectious diseases, or clinical research.