Do big government debts and fast rates of adding to them threaten our collective well-being? In this groundbreaking analysis, Ray Dalio, one of the greatest investors of our time and the #1 New York Times bestselling author of Principles, shares the reasons behind his fears for the US debt markets, answering some of the most important market and economic questions we now face: Are there limits to debt growth? Can a big, important reserve currency country like the US really go broke? Is there such a thing as a 'Big Debt Cycle' that can tell us when to worry about debt and what to do about it?