The fascinating story of two American giants—Henry Ford and Thomas Edison—whose annual summer sojourns introduced the road trip to our culture and made the automobile an essential part of modern life, even as their own relationship altered dramatically. In 1914 Henry Ford and naturalist John Burroughs visited Thomas Edison in Florida and toured the Everglades. The following year Ford, Edison, and tire maker Harvey Firestone joined together on a summer camping trip and decided to call themselves the Vagabonds. They would continue their summer road trips until 1925, when they announced that their fame made it too difficult for them to carry on. Although the Vagabonds traveled with an entourage of chefs, butlers, and others, this elite fraternity also had a serious purpose: to examine the conditions of America's roadways and improve the practicality of automobile travel. Cars were unreliable and the roads were even worse. But newspaper coverage of these...