In a collection of essays, Malcolm Gladwell explores the relationship between power and prestige on the one hand and weakness and struggle on the other. Two theses run through the essays in David and Goliath: Underdogs, Misfits, and the Art of Battling Giants. The first thesis is that in a contest where one side is obviously superior to the other by conventional standards, the weaker side often has one or more underappreciated advantages. The second thesis is that too much strength can be a bad thing—a phenomenon represented graphically by an inverted-U curve: as strength increases along the horizontal axis, the benefit, on the vertical axis, at first rises but eventually begins to fall.

The Introduction and Part One develop both claims. The first example of hidden advantage on the weaker side is David, the Biblical shepherd boy, who uses a simple sling to overcome the heavily armored and physically imposing warrior Goliath. Later examples include an unskilled girls’ basketball team that wins games with the full-court press, and T. E. Lawrence and his Bedouin guerillas, who use sabotage and surprise to defeat the Turkish army during the First World War.

The moral is that weakness encourages innovation. The basketball team, for instance, adopts the full-court press because the team stands no chance of winning by playing the way other teams do. Gladwell also considers the value of being a Big Fish in a Little Pond instead of a Little Fish in a Big Pond. The French Impressionists found success by creating a Little Pond for themselves, in the form of a self-staged exhibition. Similarly, a college student choosing between a prestigious school and a less-prestigious one will often have a better experience, and will be more successful, at the latter.

A chapter primarily about school class sizes illustrates the concept of the inverted-U curve. According to conventional wisdom, students learn more in small classes than in large ones. This is true, according to Gladwell, for class sizes above twenty-five or so. But a class size of fifteen is smaller than ideal. Family income also illustrates the point: more income is good when it enables a family to afford necessities, but not when the added income makes it harder for parents to say “no” to their children.

Part Two of David and Goliath develops both themes further. Under the right circumstances, personal difficulty can promote the development of valuable skills. Gladwell illustrates this point using several people who grew up with dyslexia. Dyslexia forced trial lawyer David Boies to become an unusually good listener, and it forced film producer Brian Grazer to become an exceptional negotiator. In IKEA founder Ingvar Kamprad and investment banker Gary Cohn, dyslexia fostered a willingness to be “disagreeable”—to do things other disapprove of, like doing business in a communist country or lying your way into a job. A tragically deprived childhood had the same effect on medical pioneer Emil Freireich, who was willing to try treatment techniques that shocked and appalled his colleagues.

Brushes with danger can cause people to become physically more courageous. Here, Gladwell’s examples include the survivors of the London Blitz in World War II and civil rights leader Fred Shuttlesworth. Many of the examples in this section are also examples of inventiveness born of necessity. Freireich, for example, had to find ways to keep his young patients alive when existing techniques were of little use. Wyatt Walker, coordinator of the Birmingham civil rights protests, had to find a way to goad police chief Bull Connor into a response that would attract the country’s attention.

Part Three and the Afterword focus on the limits of government power. Again, the lesson of the inverted-U curve regularly applies. In Belfast, Northern Ireland, in the 1960s, the British government found that applying overwhelming force without establishing legitimacy in the eyes of the population was counterproductive. Conversely, a New York police unit demonstrated that legitimacy makes traditional policing techniques more effective. When it comes to the punishment of violent crime, Gladwell argues that overly harsh sentencing policies, like California’s Three Strikes law, do more harm than good. He makes his case partly with statistics and partly by describing the contrasting ways in which two parents of different murder victims each coped with their loss.

Gladwell’s last two examples are from times of war. During World War II, officials of Vichy France recognized the limits of their power when a small village openly refused to cooperate in the arrest and deportation of Jews. And during the Vietnam War, the U.S. government learned that despite the recommendations of a confident analyst from the RAND corporation, overwhelming financial and material superiority did not guarantee victory over the Viet Cong.