Over the past century, if the wealthiest families had spent a reasonable fraction of their wealth, paid taxes, invested in the stock market, and passed their wealth down to the next generation, there would be tens of thousands of billionaire heirs to generations-old fortunes today. The puzzle of The Missing Billionaires is why you cannot find one such billionaire on any current rich list. There are a number of explanations, but this book is focused on one mistake which is of profound importance to all investors: poor risk decisions, both in investing and spending. Many of these families didn't choose bad investments-they sized them incorrectly-and allowed their spending decisions to amplify this mistake. The Missing Billionaires book offers a simple yet powerful framework for making important lifetime financial decisions in a systematic and rational way. It's for listeners with a baseline level of financial literacy, but doesn't require a PhD. Part One builds the theory of optimal investment sizing from first principles, starting with betting on biased coins. Part Two covers lifetime financial decision-making, with emphasis on the integration of investment, saving, and spending decisions. Part Three covers practical implementation details, including how to estimate the expected return and risk on a broad spectrum of investments.