[types of viruses] DNA virus; RNA virus.

[DNA viruses] herpesvirus; cytomegalovirus, CMV; human immunodefficiency virus, HIV.

Some of the time, maybe most of the time, downloading the text of the book is like taking it off the shelf at the store and looking at the cover and reading the blurbs (with the advantage of not having to come into contact with the residual DNA and burger king left behind by everyone else who browsed the book before you).