There is no need to have your students purchase a textbook with this site available, since it is based on a well written published text and has many advantages over its source material. The site is attractive, easy to navigate and the author has kept the material current. There are plenty of full color illustrations, and relevant links (including a search engine) are present for each topic. There is a nice balance between discussions of molecular and medical/epidemiological virology. The biggest disadvantage is that one either has to read from the screen or print a large volume of material. In addition, most of the material addresses animal viruses, although one can access material on bacterial and plant viruses. I have used this site as the reference/background text for my class since 1997 and the students prefer it to purchasing an expensive book.