This guy uses a PDA and laser scanner to get real-time data on used books found at library sales, junk shops, and in used book stores and purchases the undervalued ones to resell at a profit. Is he doing something skeezy or just making a (quasi-ethical) buck? He doesn’t seem too sure himself.

My scanner lies at the end of a cartridge that is fitted into a Dell PDA—a species of technology now obsolete for nearly every purpose but this one. Anyone with a smartphone can scan barcodes on books, but these people aren’t the competition, exactly. Smartphone scanner applications, which interpret photographic images of barcodes and then look up the corresponding products on the Web, work too slowly to be tools for the professional. With the PDA and laser scanner, I work at the speed of the retail cashier.

My PDA shows the range of prices that other Amazon sellers are asking for the book in question. Those listings offer me guidance on what price to set when I post the book myself and how much I’m likely to earn when the sale goes through. The scan happens fast and the prices are stored locally, in a database that I download onto the device from a third-party company. If, according to the settings I’ve plugged in, a book is sufficiently valuable, the program shows me a green “BUY” bar across the top. If it’s a dud, I see a red bar: “REJECT.”

When I first started this work, I would wake up every morning with fingers stiff from prying apart books in order to get a better look, and a clear shot at the barcode. On average, only one book in 30 will have a resale value that makes it a “BUY.” One man’s trash is, of course, nearly always another man’s trash. When I find a good one, I get a little feeling of violent achievement, and I hide the book away immediately. (Sometimes resellers will carry blankets around to throw over their piles of treasures.)