This comprehensive volume focuses on molecular methods and principles of prokaryotic and eukaryotic pathogens. The authors present the molecular and cellular aspects by focusing on the interactions between pathogenic microorganisms and their hosts. The publication begins with an overview of the most important and dangerous causative agents of infectious diseases. Next are discussions of how microbial weapons, pathogenicity factors, protein secretion machines, and surface variation systems work, presenting the molecular and genetic methods that are used by scientists for their discovery and analysis. Furthermore, infectious diseases are discussed in light of the newly formed research areas of evolutionary and cellular microbiology and genomics. Future aspects on diagnostic techniques, therapy, and vaccine development are also presented.About the Author: Joerg Hacker (PhD), studied biology at the University of Halle. In 1987 he was appointed Professor for Microbiology at the University of Wuerzburg, and since 1993 he has been a full Professor for Biology for Infectious Diseases and Head of the Institute for Infectious Disease Biology in Wuerzburg. He teaches Microbiology and Microbial Pathogenesis to undergraduates and graduate students of biology, pharmacy, and medicine, and his research is focused on molecular mechanisms of pathogenesis, gene regulation of microbial genes and studies on the evolution of pathogens. He is also a member of several editorial boards and scientific societies in different countries. Juergen Heesemann (MD, PhD) studied physical chemistry (PhD) at the University of Hamburg and medicine (MD) at the University of Goettingen. From 1989 to 1995 he held the chair of Medical Microbiology of the University of Wuerzburg. Since 1996 he has been Professor of Medical Microbiology at the University of Munich where he teaches medical microbiology to undergraduate and graduate students of medicine and biology. Most of his research has been on the molecular analysis of pathogenesis of Yersinia enterocolitica including aspects of cellular microbiology, host immune response, vaccine development and evolution of pathogenicity. Juergen Heesemann is also a member of several editorial boards: Infection and Immunity, International Journal of Medical Microbiology, Medical Microbiology and Immunology, European Journal of Clinical Microbiology and Infectious Diseases.