Smallpox in Human History -- Classification of Poxviruses and Brief Characterization of the Genus Orthopoxvirus -- Vaccinia Virus -- Variola (Smallpox) Virus -- Monkeypox Virus -- Cowpox Virus -- Molecular Evolution of Orthopoxviruses -- Laboratory Diagnostics of Human Orthopoxvirus Infections -- Preparedness and Response to Potential Bioterrorism. Orthopoxviruses Pathogenic for Humans covers those viruses capable of causing disease in man, including monkeypox, smallpox, cowpox, and vaccinia. The coverage of each virus is comprehensive, covering the biology, molecular biology, and ecology of the virus as well as the clinical and epidemiological aspects of these viruses in humans and animals. In addition, this volume highlights developments in genetic engineering that are paving the way for potential therapeutic treatments of these viruses.