Oh, that's great! Books are my weakness too. Especially cook books and children's books. I have a couple of boxes in the garage that I need to donate but "haven't got around to yet". I am so attached to my books, yet rarely have the leisure to read anymore. Good luck! My feeling is that especially for the ones that were already in the garage it will be OK to send them off fondly, wishing them well. Refining my bookshelves is something I am constantly doing. I like to have a little bit of space on them too, and I have to say, I've never regretted it yet.
Mama to 13, and 10 and 4.