One of the most useful modifications that have been made to viruses is the ability to encode tracers such as green fluorescent protein (GFP), facilitating the investigation of infectivity, replication and pathogenesis, thereby allowing not only study of the virus itself, but also the behaviour of infected cells. As the title indicates, it is a methods text, giving useful practical details important to those attempting to carry out similar studies. The book is supplied with a CD containing videos and colour versions of some of the monochrome figures in the book. I would have much preferred for the colour figures to appear in the book itself; however, I appreciate that this significantly increases costs. Perhaps it might have been better to have gone all the way and published the title as an 'e.book'. The subject and price of the book is likely to restrict its purchase to research institutions.