FBReader (at least on Android devices) will show the front cover and a description of the book when you tap on it. You can then go back to select another book or tap again to read the book.

Long tapping on a book on Kobo ereaders will show the front cover plus synopsis.

The benefit of this approach, over adding the description as part of the book's content, is speed and ease of use. (Examples: you don't have to wait for the book to load, navigate to the description page, or fiddle around with calibre.)