When Vivek Ranadivé decided to coach his daughter Anjali’s basketball team, he settled on two principles. The first was that he would never raise his voice. This was National Junior Basketball—the Little League of basketball. The team was made up mostly of twelve-year-olds, and twelve-year-olds, he knew from experience, did not respond well to shouting. He would conduct business on the basketball court, he decided, the same way he conducted business at his software firm. He would speak calmly and softly, and convince the girls of the wisdom of his approach with appeals to reason and common sense.

The second principle was more important. Ranadivé was puzzled by the way Americans played basketball. He is from Mumbai. He grew up with cricket and soccer. He would never forget the first time he saw a basketball game. He thought it was mindless. Team A would score and then immediately retreat to its own end of the court. Team B would inbound the ball and dribble it into Team A’s end, where Team A was patiently waiting. Then the process would reverse itself. A basketball court was ninety-four feet long. But most of the time a team defended only about twenty-four feet of that, conceding the other seventy feet. Occasionally, teams would play a full-court press—that is, they would contest their opponent’s attempt to advance the ball up the court. But they would do it for only a few minutes at a time. It was as if there were a kind of conspiracy in the basketball world about the way the game ought to be played, and Ranadivé thought that that conspiracy had the effect of widening the gap between good teams and weak teams. Good teams, after all, had players who were tall and could dribble and shoot well; they could crisply execute their carefully prepared plays in their opponent’s end. Why, then, did weak teams play in a way that made it easy for good teams to do the very things that made them so good?

Ranadivé looked at his girls. Morgan and Julia were serious basketball players. But Nicky, Angela, Dani, Holly, Annika, and his own daughter, Anjali, had never played the game before. They weren’t all that tall. They couldn’t shoot. They weren’t particularly adept at dribbling. They were not the sort who played pickup games at the playground every evening. Most of them were, as Ranadivé says, “little blond girls” from Menlo Park and Redwood City, the heart of Silicon Valley. These were the daughters of computer programmers and people with graduate degrees. They worked on science projects, and read books, and went on ski vacations with their parents, and dreamed about growing up to be marine biologists. Ranadivé knew that if they played the conventional way—if they let their opponents dribble the ball up the court without opposition—they would almost certainly lose to the girls for whom basketball was a passion. Ranadivé came to America as a seventeen-year-old, with fifty dollars in his pocket. He was not one to accept losing easily. His second principle, then, was that his team would play a real full-court press, every game, all the time. The team ended up at the national championships. “It was really random,” Anjali Ranadivé said. “I mean, my father had never played basketball before.”

David’s victory over Goliath, in the Biblical account, is held to be an anomaly. It was not. Davids win all the time. The political scientist Ivan Arreguín-Toft recently looked at every war fought in the past two hundred years between strong and weak combatants. The Goliaths, he found, won in 71.5 per cent of the cases. That is a remarkable fact. Arreguín-Toft was analyzing conflicts in which one side was at least ten times as powerful—in terms of armed might and population—as its opponent, and even in those lopsided contests the underdog won almost a third of the time.

In the Biblical story of David and Goliath, David initially put on a coat of mail and a brass helmet and girded himself with a sword: he prepared to wage a conventional battle of swords against Goliath. But then he stopped. “I cannot walk in these, for I am unused to it,” he said (in Robert Alter’s translation), and picked up those five smooth stones. What happened, Arreguín-Toft wondered, when the underdogs likewise acknowledged their weakness and chose an unconventional strategy? He went back and re-analyzed his data. In those cases, David’s winning percentage went from 28.5 to 63.6. When underdogs choose not to play by Goliath’s rules, they win, Arreguín-Toft concluded, “even when everything we think we know about power says they shouldn’t.”

Consider the way T. E. Lawrence (or, as he is better known, Lawrence of Arabia) led the revolt against the Ottoman Army occupying Arabia near the end of the First World War. The British were helping the Arabs in their uprising, and the initial focus was Medina, the city at the end of a long railroad that the Turks had built, running south from Damascus and down through the Hejaz desert. The Turks had amassed a large force in Medina, and the British leadership wanted Lawrence to gather the Arabs and destroy the Turkish garrison there, before the Turks could threaten the entire region.

But when Lawrence looked at his ragtag band of Bedouin fighters he realized that a direct attack on Medina would never succeed. And why did taking the city matter, anyway? The Turks sat in Medina “on the defensive, immobile.” There were so many of them, consuming so much food and fuel and water, that they could hardly make a major move across the desert. Instead of attacking the Turks at their point of strength, Lawrence reasoned, he ought to attack them where they were weak—along the vast, largely unguarded length of railway line that was their connection to Damascus. Instead of focussing his attention on Medina, he should wage war over the broadest territory possible.

The Bedouins under Lawrence’s command were not, in conventional terms, skilled troops. They were nomads. Sir Reginald Wingate, one of the British commanders in the region, called them “an untrained rabble, most of whom have never fired a rifle.” But they were tough and they were mobile. The typical Bedouin soldier carried no more than a rifle, a hundred rounds of ammunition, forty-five pounds of flour, and a pint of drinking water, which meant that he could travel as much as a hundred and ten miles a day across the desert, even in summer. “Our cards were speed and time, not hitting power,” Lawrence wrote. “Our largest available resources were the tribesmen, men quite unused to formal warfare, whose assets were movement, endurance, individual intelligence, knowledge of the country, courage.” The eighteenth-century general Maurice de Saxe famously said that the art of war was about legs, not arms, and Lawrence’s troops were all legs. In one typical stretch, in the spring of 1917, his men dynamited sixty rails and cut a telegraph line at Buair on March 24th, sabotaged a train and twenty-five rails at Abu al-Naam on March 25th, dynamited fifteen rails and cut a telegraph line at Istabl Antar on March 27th, raided a Turkish garrison and derailed a train on March 29th, returned to Buair and sabotaged the railway line again on March 31st, dynamited eleven rails at Hediah on April 3rd, raided the train line in the area of Wadi Dhaiji on April 4th and 5th, and attacked twice on April 6th.