Military history is a gallimaufry of choices and chance, of opportunities taken, of roads forsaken.
It is this truism that drives What If? (Putnam; 305 pages; $27.95), a collection of essays by 34 military historians, journalists and novelists, all indulging in "counterfactual" conjecture.
In 334 B.C., for example, the 22-year-old Macedonian King Alexander charged with his cavalry into the ranks of Persian forces at the Granicus River in what is now Turkey. A Persian soldier clubbed Alexander with an ax, but before he could deal a second and fatal blow, the King's bodyguard killed him.
What if Alexander had died...