People could book 15-minute slots to enjoy a free six-inch pie. Did I want to talk to some of them? Surely, I thought, at least a few of these pizza lovers had to be former Book It! kids.

Pizza Hut’s Book It! literacy program, founded in 1984, has reached more than 70 million students — and counts the radio host Charlamagne Tha God among its fans. By Sarah Bahr Sarah Bahr was a ...