America's Richest Families: A Forbes Compendium Of Stories Since 1977;

Forbes compiled the first ranking of the richest families in 2014, but has written about these storied clans for nearly 100 years. One thing we’ve found: The ability to efficiently hand control over within a family empire is easier said than done. Forbes’ Kerry Dolan says, “Hard as it is to build a family business designed to last in perpetuity, it’s shockingly easy for any successor to tank it.”

These families have passed the tests of time and maintained their wealth for generations. To value their fortunes, we added up their assets and took into account estimates of debt. The wealthiest American family in 2015 is the Waltons, followed by the Koch brothers and the Mars family. Together, these three families are worth $315 billion, one-fourth of the cumulative net worth of all the wealthiest families.

The stories offered in this book focus on the 10 richest families in America, along with a few others we deemed worthy of an appearance. These stories provide a snapshot into the lives of America’s richest families, and how they built—and sustained—their empires.