[ProDigit]

It is actually creating an e-book that takes the longest.
You can create ebooks in 3 ways:
1- the simply putting a text book in another e-format jacket,
2- Finding and scanning (original) pictures to add to the book
3- Scanning a book, and/or correcting electronic errors before creating a book

The first does not take a lot of time. You can create an ebook in 15 minutes.
The second takes slightly longer, on average you'll lose a good few hours per book.
The third one takes longest. You can easily spend between 4 to 90 hours per book, correcting spelling errors,creating hyperlinks, and scanning a book itself do take up a lot of time.
Because I have the time, I figured I'd better do the hardest books, since most people will prefer directly converting Gutenberg books to e-formats.

If it's a good ebook, I tend to read it while creating it on my PC. That takes an additional time toll.