This book addresses the unique features of four microorganisms that constitute the top bioterror threat agents: Bacillus anthracis; Yersinia pestis, Francisella tularensis and Orthopoxviruses. Side-by-side updated information about their pathogenisis, virulence and epidemiology is provided in a single volume, allowing for evaluation of common features as well as common strategies for defense. Classical microbiological as well as genomic, proteomic & transcriptomic approaches towards development of strategies of novel prophylactic and post-exposure treatment and related aspects of diagnostics and bioforensics are covered. Written by top scientists, this book will be of major interest to all researchers interested in the intricate biology of highly pathogenic microorganisms, to scientists and clinicians interested in microbial pathogenesis and prevention, and to a wide range of professionals dealing with the various aspects of bio-defense.