What is the most versatile e-book format?

Question

ASP.NET

I plan to develop a reader for books of various formats using .NET technologies. The question arises of how to deal with all the available formats of books. The first thing that comes to mind is to bring all downloadable formats to one (pdf for example) and then give it to the client. A logical question: what format is the most universal, to which it is rational to bring all downloaded books. So far, I have settled on the fact that all books are page-by-page rendered into images (jpg for example). However, sooner or later the task of working with text (scaling, highlighting, etc.) will arise, where working with Jpg will be a headache, some kind of text recognition will be needed. Tell me how best to proceed?

Answer 1

where did the task come from in the first place? those. what problem are we solving? the most common formats - epub, fb2, pdf - there are readers for everything (yes, even plugins for firefox)
download any book in the right format (or convert online for free) - also not a problem at all ... or so - you want to warm up your hands pee code?

Answer 2

Well, look at the formats in which large and thick libraries like libruseks are stored, write your own cataloger and viewer.
It is unlikely that anyone will need it, but you will really get certain skills in this direction.