Provides an essential introduction to modern virology. Focussing on the new molecular approach, this textbook presents the principles of virology in a clear and concise manner that will give students of biology or medicine a broad, comprehensive understanding of the subject. The text explores and explains the fundamental aspects of virology including structure of virus particles and virus genomes, virus replication, control of gene expression, and virus pathogenesis (including AIDS). Later chapters consider the major current concerns in virology, such as responses to and treatment of virus infections, and the emergence of novel infectious agents including viruses, viroids and prions. The book is illustrated with over 100 clear line drawings, which complement the text. The summaries at the end of each chapter provide an excellent revision aid.