Virology is a fascinating subject, with viruses inhabiting a twilight world somewhere in-between the animate and inanimate. The Latin word virus, means ' poisonous fluid'. Viruses are essentially intracellular parasites, unable to reproduce themselves outside living cells. Virology is a relatively new science, having to await the invention of the electron microscope before real progress in elucidating the viral structure and function could be made. The third edition of Collier and Oxford's, Human Virology builds on the strengths of the previous editions. Students are often overwhelmed with information, and this book acknowledges this fact by presenting factual information in a user-friendly and accessible format which piques student interest and painlessly encourages retention of facts. The authors' intent is not to turn their readers into virologists but rather to provide them with enough knowledge of the nature of viruses and virus infections to serve as an essential background for later involvement with the subject. The new edition has been extensively updated, with many new diagrams included. New material has been added on: DT Plant and bacterial viruses DT Coronaviruses, focusing on SARS DT Monkeypox infections in humans and the possible use of smallpox as a biological weapon DT Latest advances on chemotherapy of herpesviruses DT Updated material on Prion diseases, focusing on new variant CJD. DT New material on the debate between MMR versus single vaccine.