Now in four convenient volumes, Fi ld's Virology remains the most authoritative reference in this fast-changing field, providing definitive coverage of virology, including virus biology as well as replication and medical aspects of specific virus families. This volume of Fi ld's Virology: Fundamentals, Seventh Edition, edited by Drs. Peter Howley and David M. Knipe, along with volume associate editors Drs. Lynn Enquist, Jeffrey I. Cohen, Eric O. Freed, Blossom A. Damania, and Sean P. J. Whelan, focuses on the basic principles of virology and reflects recent advances in this dynamic fie  .