When some one ask about our library if we had read all of our books there are 3 possible answers: 1) of course! 2) if i had read them all, why would i keep having them? 3) of course not, having a book doesn't mean to have to read it! To me, it's a kind of magic/mistery to have a book: you really don't know what you will find on it until you read it, but after that, every visitation is another discover. Even if you don't read it, you will always ask what could you find on it! It's all about content.
Its funny because i had the same expirence with a book of Kropotkin not a long time ago. I'm afraid to have "too many" books but i dont know if this is really possible. I would like to have just ten of them and read them for ten years and after that give them to someone and find more ten for the next decade.