WHILE STICKING price tags on a stack of pawned books at Powell’s on New Year’s Day 2004, my coworker handed me a Webster’s dictionary. “Look,” he said, pointing to blue ink on the title page. “This person didn’t waste any time.” The inscription read: “Merry Christmas 2003!” Daydreaming, I wondered if the owner might not have been given it by his estranged mother, an English teacher who nitpicked her son’s grammar growing up. Only a few days after receiving it, he must have sold the book to ward off bad memories of his childhood torment. My heart went out to him.

On another day, I was cleaning up a few hundred used books to ready them for shelving. From a 1901 edition of Ernest Thompson Seton’s Lives of the Hunted, I erased the words “To Philip, from Mama,” and then felt as though I’d just driven a tractor through a graveyard, knocking over the headstones.

In the six years that I worked at Powell’s, I encountered other evidence of the multiple and sordid lives of books: naked photos, handwritten notes, 30-year-old postcards, flattened joints, receipts from stores that no longer exist. All slipped between pages. All forgotten. Most clerks just threw this stuff away. After all, with each of us acting as a kind of biblio-adoption agent, we were merely expected to facilitate the smooth transition between a book’s former owner and its future one, not to invest the pages with emotion or meaning. Instead I tended toward the sentimental: I stored these artifacts in manila envelopes labeled “Powell’s Found Items,” and I began to see such traces as unrecorded layers of exhausted love.

But while all the inscriptions and bookplates and artifacts held in those pages had the potential to expose rifts in past relationships, I also came to see the books that surrounded me each day as catalysts for relationships that had yet to form. People passing each other in the crafts aisle might pause briefly at the same shelf, might be drawn to each other—even moved to speak to each other—by the magnetism of a book like Simple Screenprinting. For me, the stacks at Powell’s became barometers of social, romantic, and intellectual compatibility. It was no Myers-Briggs personality test (and my flimsy synopsis makes it sound like a literary zodiac), but really, if I ask a woman what she’s reading and she says Dr. Phil, is there any hope for us?

I worked in the science section for the majority of my time at Powell’s, so I pined for a certain species of reader to appear—like the gorgeous woman in hiking boots and glasses who once browsed my canids and small-mammals subsections. I asked if she needed help and she blurted, “Cool!” while holding up Lone Pine’s Squirrels of the West guide. “I have to have this,” she said.

“That,” I said, “is the best field guide on western squirrels I’ve yet seen.” Yes, What incredible geeks, you’re thinking, but that’s the core of what I like to call my Barometric Book Theory. Just as any trained biologist or serious outdoorswoman would, she used the word ungulates to describe the elk and deer family and named Pojar’s Plants of the Pacific Northwest Coast as a favorite. And so I pressed further, testing her tolerance. “Do you like bats?”