“Rockefeller was a strange guy. But he figured out something that now applies to tens of millions of workers. Rockefeller’s job wasn’t to drill wells, load trains, or move barrels. It was to think and make good decisions. Rockefeller’s product—his deliverable—wasn’t what he did with his hands, or even his words. It was what he figured out inside his head. So that’s where he spent most of his time and energy. Despite sitting quietly most of the day in what might have looked like free time or leisure hours to most people, he was constantly working in his mind, thinking problems through. This was unique in his day. Almost all jobs during Rockefeller’s time required doing things with your hands. In 1870, 46% of jobs were in agriculture, and 35% were in crafts or manufacturing, according to economist Robert Gordon. Few professions relied on a worker’s brain. You didn’t think; you labored, without interruption, and your work was visible and tangible. Today, that’s flipped. Thirty-eight percent of jobs are now designated as “managers, officials, and professionals.” These are decision-making jobs. Another 41% are service jobs that often rely on your thoughts as much as your actions.”