There's a lovely piece about bookshelves and book collections at The Millions by Kevin Hartnett. I want to quote the last three paragraphs (down there) because I think he hits it on the head and because I found it quite touching. I'm sure most people have had similar experiences. It also states the case for books and bookshelves as displays and catalogues of people's tastes and personalities much better than this snobby bitch does, boo snobby bitches:

if you don’t read, I don’t want to be your friend…I don’t even want you to serve me a drink at a bar. If a stranger came over to our apartment, and there weren’t books, or–oh no!–not enough books, what would that say about me and Patrick? If my copy of Handmaid’s Tale or his copy of The Power Broker weren’t on display, how would anyone understand us? Some people have a cross in their home, or a mezuzah on their doorjamb. I’ve got nine books by Vladimir Nabokov.

I got THIRTY books by Valerie Tripp, bitch. Suck it. I'm kidding. But anyway, ew, not cool. People like this make me want to put all my, like, Dragonlance books in the foyer and make 'em stand next to them at a cocktail party while I talk about how I would never be friends with someone who doesn't read, like all those kids our school system is churning out, those people with empty, empty lives. Minorities, too, mostly the brown ones, though. African orphans. Blind people. "They're not really reading, you know? They're turning a purely intellectually pursuit into a physical activity. Another PBR, you down to earth American original, you?"

I'm also quoting a big chunk of it because I'm becoming an old lady who views all this new technology with deep suspicion and says things like "the rise of the machines" and "corporate creation of instant gratification addiction, just like they gave crack to the ghetto" and "kids on my lawn." Okay, here's the quote. Emph mine.

Of the bookshelves I’ve inspected in my life, two stand out as particularly consequential. The first was my mother’s, which was built into the wall of the bedroom where she grew up. When I would visit my grandparents in the summer I would spend hours inspecting that bookshelf. The books were yellowed and jammed tightly together, as though my mother had known it was time to leave home once she no longer had any room left on her shelves. In the 1960s novels, the Victorian classics, and the freshman year sociology textbooks fossilized on the bookshelf, I got the clearest glimpse I ever had of my mother as a person who existed before me and apart from me, and whose inner life was as bottomless as I knew my own to be.

And then there was my wife, whose bookshelves I first inspected in a humid DC summer, while her parents were away at work. The shelves were stuffed full of novels—Little House on the Prairie, The Andromeda Strain, One Hundred Years of Solitude—that described an arc of discovery I had followed too. At the time we met, her books still quivered from recent use and still radiated traces of the adolescent wonder they’d prompted. In the years since, on visits home for the holidays and to celebrate engagements and births, I’ve watched her bookshelves dim and settle. Lately they’ve begun to resemble a type of monument I recognize from my mother’s room. They sit there waiting for the day when our son will be old enough to spend his own afternoons puzzling out a picture of his mother in the books she left behind.

It remains to be seen how many more generations will have the adventure of getting to know their parents in just this way. One for sure, and maybe two, but not much beyond that I wouldn’t think. To the extent that bookshelves persist, it will be in self-conscious form, as display cases filled with only the books we valued enough to acquire and preserve in hard copy. The more interesting story, however, the open-ended, undirected progression of a life defined by books will surely be lost to a digital world in which there is no such thing as time at all.

This also might explain it. We have 3 more similar shelves in a very small apartment. I like touching books. My parents' house has about a bazillion more. I used to find books that I later had to read at school, the same school by father went to. It was cool.