Literature
The largest range of e-book is devoted to literature. These are good for storage space, seeing as a whole library can fin into a small pad.
Reference materials
The second most popular type of e-book is used for referencing material. Possibilities for these would be instruction manuals, encyclopedias,
Children's books
Children's e-books are the least popular of all 3 types of e-book (maybe because of the age range?).
