Of course I judge people by their bookshelves. When I come into someone's home, I gravitate towards them like a moth to flame. I strain my eyes to see what books complete strangers are reading on the plane, on the subway, at the pool. If a friend raves or rants about a book on Facebook, it could completely change my opinion of her. I almost broke up with a boyfriend because his favorite book of all time was Catcher in the Rye (and he was almost thirty) but the other books on his bookshelves gave him a second chance. I think these judgments are fair game and I am pretty confidant about them.
However, the reverse doesn't work well for me. Friends or family will come over to my house, they'll peruse my bookshelves, and they'll say, "Oh, what did you think of The Nightingale? Isn't it wonderful?" and I'll say, "I don't know. I haven't read it yet. I've heard good things, though." And then they might follow it with, "Oh, but you must have loved Summer Secrets! I adore Jane Green," And I'll have to answer, "I've liked some of her books too, but I haven't read that one yet." You see, all the books in my bookcases are books I haven't read. So it's not really fair to use them to make a judgment of me because I don't know yet whether or not I like them. You can judge me based on what books I want to read, but that's different than judging based on books I've read and loved and collected.
In my defense, I have a lot of books. I've worked in the book industry for more than twenty years, so I have friends who send me books, I'm on a couple of publishers' lists, I have maxed out my reserve list at the library, and I do buy well more than my fair share of books at bookstores. I have currently more than four hundred books in my house that I haven't read yet. If I were to keep all the books I read, on top of the books I haven't yet gotten to, I fear I would die, crushed to death in an avalanche of my own creation (or if I slowly starved with my two broken legs, at least I could read a few more books before I died.)
Yes, I do have a handful of books I hang on to. There's a skinny bookcase tucked away in a corner with classics and some antique editions and other nice, gift-book editions of favorites. Upstairs in my bedroom, I have a shelf of old beloveds, and another shelf of loved children's books. And in my office, a shelf of the books I acquired when I was an editor at St. Martin's Press. But for the majority of books, I want them to go on to a good home. I want to spread the wealth, to encourage more reading. And I need to clear some space on my shelves so I can buy more books!