Since 9/11, why have we won smashing battlefield victories only to botch nearly everything that comes next? In the opening phases of war in Afghanistan, Iraq, and Libya, we mopped the floor with our enemies. But in short order, things went horribly wrong. We soon discovered we had no coherent plan to manage the "day after". The ensuing debacles had truly staggering consequences - many thousands of lives lost, trillions of dollars squandered, and the apparent discrediting of our foreign policy establishment.

Unlike the wars in Vietnam and Iraq, the US invasion of Afghanistan in 2001 had near-unanimous public support. At first, the goals were straightforward and clear: Defeat al-Qaeda and prevent a repeat of 9/11. Yet soon after the United States and its allies removed the Taliban from power, the mission veered off-course and US officials lost sight of their original objectives.

The wars in Iraq and Afghanistan have taken a tremendous toll on the mental health of our troops. In 2005, then-Senator Barack Obama took to the Senate floor to tell his colleagues that "many of our injured soldiers are returning from Iraq with traumatic brain injury", which doctors were calling the "signature wound" of the Iraq War. Alarming stories of veterans taking their own lives raised a host of vital questions: For instance, why hadn't the military been better prepared to treat post-traumatic stress disorder (PTSD) and traumatic brain injury (TBI)?

Games are everywhere: Drivers maneuvering in heavy traffic are playing a driving game. Bargain hunters bidding on eBay are playing an auctioning game. The supermarket's price for corn flakes is decided by playing an economic game. This Very Short Introduction offers a succinct tour of the fascinating world of game theory, a groundbreaking field that analyzes how to play games in a rational way. 

By the late 1960s, what had been widely heralded as the best qualified, best-trained army in United States history was descending into crisis as the Vietnam War raged without end. Morale was tanking. AWOL rates were rising. And in August 1968, a group of Black soldiers seized control of the infamous Long Binh Jail, burned buildings, and beat a white inmate to death with a shovel. The days of "same mud, same blood" were over, and a new generation of Black GIs had decisively rejected the slights and institutional racism their forefathers had endured.