Accounting and Cost Control
The same chapter from every series, so you can compare how each fortune was built. Other posts on the topic follow.
Rockefeller (Part 2 of 5), Accounting: 39 Drops of Solder and a Barrel of His Own
How Rockefeller tracked costs to a fraction of a cent, made his own barrels, and turned waste into products.
Onassis (Part 2 of 5), Accounting: Cost per Ton, Bigger Ships, Smaller Crews, Offshore Structures
Why bigger ships, smaller crews, and offshore structures cut his cost per ton.