There are many PDF reader tools that add text highlighting capabilities, e.g.
But what about academic books? Electronic versions of scientific or computer books are convenient (you can easily search in them), but you still miss out underlining and highlighting paragraphs, scribbling explanations, annotations and other such hard-copy operations that help you revise a book. When it comes to timewasting books like novels you read on holidays, e-books are preferable. There are two kinds of people in the world, those that prefer traditional printed books, and those that go for electronic versions thereof (e-books, PDF documents etc).
■ Annotate PDF books using Sumatra PDF reader
