Chlamydia is an important bacterial pathogen and a major cause of human and animal disease. Each year, more cases of chlamydial infection are reported to the Centers for Disease Control and Prevention than all other infections combined, illustrating its enormous public health impact. This book provides an up-to-date review of the clinical infections caused by the two main human pathogens C. trachomatis and C. pneumoniae, as well as chapters on veterinary Chlamydia species and Chlamydia-related bacteria. Multiple chapters cover cutting-edge developments in Chlamydia research, from the basic biology of the intracellular chlamydial infection to the host immune response and work towards a Chlamydia vaccine. Also highlighted are recent advances in chlamydial genetics and genomics, which have transformed the field. For the first time in a Chlamydia book, there are chapters on Chlamydia cell division and differentiation and Chlamydia infections and the microbiota, which are two hot areas of research. Each of the nineteen chapters is written by experts, who have made major contributions through their work and come from different research groups to ensure a broad and fresh perspective. This book will be of interest to Chlamydia researchers, microbiologists, cell biologists, infectious disease clinicians, public health professionals and government policy makers. It will be especially useful for newcomers to the Chlamydia field, who will find a current and comprehensive summary of Chlamydia research in one volume.