In 1980, Gaston Glock was the manager of a car-radiator factory just outside Vienna. At home, he ran a side business in his garage, making knives and bayonets for the Austrian army. He lived in a comfortable though not overly prosperous way, all but unknown beyond his corner of Austria. He knew next to nothing about firearms. Less than 20 years later, he was the world's leading manufacturer of handguns, and the business born in his garage had annual revenues of more than $100 million.

If...