I'd suggest allowing users to submit short reviews of each ebook. I'd imagine it would be useful to have some insight as to which book would be most helpful for different circumstances - especially once you start to get some more submissions and there are more books per category.
From the link, here's a quote:
>There have been other pages of recommended reading on Less Wrong before (and elsewhere), but this post is unique. Here are the rules:
- Post the title of your favorite textbook on a given subject.
- You must have read at least two other textbooks on that same subject.
- You must briefly name the other books you've read on the subject and explain why you think your chosen textbook is superior to them.