• Andrew Carnegie, John D. Rockefeller, Jay Gould, and John Pierpont Morgan were all in their late twenties or early thirties, all on the first rungs of their careers, in the waning days of the Civil War. In an age of outsized business leaders, no others played so great a role in shaping and channeling the American boom. They forced the pace, drove the transition to ever-larger scales, and, for good and for ill, imposed personal stamps on the national economy that persisted well into the twentieth century.

• “[It is] best for all to leave each man free to acquire property as fast as he can. Some will get wealthy. I don’t believe in a law to prevent a man from getting rich [but] . . . we do wish to allow the humblest man an equal chance to get rich with everyone else.”

• the most prominent of the cadre the press dubbed “The Robber Barons,” and by their sheer intelligence, their ambition, and their forcefulness, they laid down the channels that other people followed.

• Carnegie, Rockefeller, and Gould personified the unlimited entrepreneurial opportunities suddenly opened by America’s vast resources and its freedom from constraints of class and caste.

• He was as relentless in self-improvement as in everything else, reading voraciously, and working hard on his accent and grammar.

• Carnegie technique: focus on an objective, then cut brutally through any conventions, competitors, or ordinary people who stood in your way.

• He was also far better read than most of his peers, with an acquired, but genuine, taste for art and culture, and an attractive writing style. Indeed, he constantly questioned whether he was squandering his talents in business. When his investment income passed the $50,000 mark in 1868, he promised himself that he would work for just two more years to secure that level of income for life, and then devote himself to finer pursuits. He was kidding himself. The core fact about Carnegie was the drive to dominate—at all costs.

• It is no surprise that the faults, and occasionally the crimes, of the great tycoons are on the scale of their achievements, but none but Carnegie was so repellantly smarmy.

• The crowning deal of Morgan’s long career was his buyout of the Carnegie Company in 1901 to create the United States Steel Corporation; in constant dollars, it was the biggest corporate transaction in history until the buyout boom of the 1980s.

• Perhaps in reaction to his father’s behavior, John was the most sober and industrious of young men—diligent at school, serious about his Baptist religion, scrupulously honest, utterly reliable.

• Rockefeller picked the location—situated for maximum access to rail and water transport. And as he gradually became obsessed with the opportunities in oil, he took over the day-to-day operations of the business while Andrews ran the refinery. Andrews was an excellent refiner, and his products quickly gained a high reputation; most important, he had the sense to recognize that John, young as he was, should make the business calls.

• For the first time, Rockefeller could demonstrate his extraordinary ability to combine headlong expansion with fanatical attention to efficiency and cost.

• The muckraker Ida Tarbell once dismissed Rockefeller as a man with the “soul of a bookkeeper,” an image that has stuck to him ever since. It was true that he loved the completeness and concreteness of good ledgers, and insisted that every entry, every tally, every invoice had to be right; but the “bookkeeper” label does not begin to capture the reality of John D. Rockefeller. If he lacked Morgan’s rhinoceros presence or Carnegie’s noisy panache, he made up for it with an extraordinary, quiet charisma.

• Move with shocking speed and minimum fanfare. Act with total confidence, but turn on a dime if new facts warrant. March in service of a sweeping vision, but pay obsessive attention to the details.

• Most extraordinary, perhaps, was Gould’s ability to sustain reverses that would crush another man, then to pull himself off the floor and to carry on, learning more, working harder, never complaining, just looking for the next chance.

• Between 1855 and 1865, net foreign investment in America had doubled; in the decade to 1875, it tripled.

• A true corner is the slaughter of the bears. A bear who shorts by borrowing and selling a security needs to buy it, or borrow it again, when the borrowing term is up. As the week went on, the short position grew to some $200 million in gold, probably most of it owed to Gould and Fisk, who were lending out all the gold they bought. The $20 million in available gold, that is, was being borrowed and sold over and over, and as the price kept rising, the bears got into a deeper and deeper hole. As Gould disgustedly put it: “[W]hat put gold up so high is that these bears got frightened, and they commenced jumping over each other’s shoulders for it. The worst panics ever produced are bear panics.”

• Time and again through a long career he absorbed fearsome blows, stoically regathered himself, and plunged back into the fray.

• Most executives might have considered the “Conquest of Cleveland” the work of a lifetime. But Rockefeller was only thirty-three, and was just getting started.