Why do catastrophes happen? What sets off earthquakes, for example? What about mass extinctions of species? The outbreak of major wars? Massive traffic jams that seem to appear out of nowhere? Why does the stock market periodically suffer dramatic crashes? Why do some forest fires become superheated infernos that rage totally out of control? Experts have never been able to explain the causes of any of these disasters. Now scientists have discovered that these seemingly unrelated cataclysms, both natural and human, almost certainly all happen for one fundamental reason. More than that, there is not and never will be any way to predict them. Critically acclaimed science journalist Mark Buchanan tells the fascinating story of the discovery that there is a natural structure of instability woven into the fabric of our world. From humble beginnings studying the physics of sandpiles, scientists have learned that an astonishing range of things–Earth’s crust, cars on a highway, the market for stocks, and the tightly woven networks of human society–have a natural tendency to organize themselves into what’s called the “critical state,” in which they are poised on what Buchanan describes as the “knife-edge of instability.” The more places scientists have looked for the critical state, the more places they’ve found it, and some believe that the pervasiveness of instability must now be seen as a fundamental feature of our world. Ubiquity is packed with stories of real-life catastrophes, such as the huge earthquake that in 1995 hit Kobe, Japan, killing 5,000 people; the forest fires that ravaged Yellowstone National Park in 1988; the stock market crash of 1987; the mass extinction that killed off the dinosaurs; and the outbreak of World War I. Combining literary flair with scientific rigor, Buchanan introduces the researchers who have pieced together the evidence of the critical state, explaining their ingenious work and unexpected insights in beautifully lucid prose. At the dawn of this new century, Buchanan reveals, we are witnessing the emergence of an extraordinarily powerful new field of science that will help us comprehend the bewildering and unruly rhythms that dominate our lives and may even lead to a true science of the dynamics of human culture and history.