I recently read the book, Pizza - A Global History, by Carol Helstosky. This is a great book for anyone in the pizza business, or even a big pizza fan.
It describes the origins of pizza in Naples, Italy, including why it was popular, what it was made with, and who likely ate it. It then explains the growth of pizza in the US and worldwide, including chains like Pizza Hut and Dominos.
It also spends some time discussing pizza references in pop culture, including a scene that I left out of my top 10 pizza movies list, in Saturday Night Fever when John Travolta eats a slice.