Book Short: Unsung Heroes If you like “entrepreneurship by analogy” books, you’ll like The Innovators: The Engineering Pioneers Who Made America Modern, by David Billington. I have to admit some bias here — Professor Billington was my favorite teacher and senior thesis advisor at Princeton (I almost majored in civil engineering because of him), and this book is one of a number he’s written that are outgrowths of his most popular courses at Princeton. And while there’s no substitute for the length or energy of his lectures, the book works. The book is basically a person-focused engineering history of America from 1776-1883. Billington talks about four classes of engineering product: public structures (mostly bridges), machines that produced power, networks like…