The 4 th Edition of Basic Virology continues to provide a more solid understanding of the basic principles and offers a comprehensive introduction to the fundamentals of virology. More enhanced features and information include emerging viruses of medical importance, viral pathogenesis, viral immunology, retroviruses and HIV/AIDS, generation and use of recombinant viruses and virus-like particles, viral evolution, network biology and viruses, and animal models and transgenics. The text has been revised to include more review questions, case studies, and cumulative end of section problems. Basic Virology is supported by website - www.blackwellpublishing.com/wagner - including original animations, downloadable artwork, and online resources designed to provide both students and instructors with an enhanced understanding of the field.