The current global conflicts are based on each side seeing the other as purely evil. The political benefit of calling something evil is that it silences debate: it dehumanizes the enemy, and makes killing that evil the only response.

Lawrence Wright is more concerned with the ascertainable roots of Osama bin Laden's murderous ideology — and the history of the men who implemented it — than with the metaphysical notion of evil. His book traces the origins of radical Islamism from Sayyid Qutb, who returned to Egypt in the 1950s from a sojourn in the US, aghast at the prurient state of secular society, to Ayman al-Zawahiri, who manipulated theology to justify his organization's increasingly savage methods. Bin Laden's story is familiar by now, but one of the many surprises in Wright's account is the extent of Zawahiri's influence: in many ways, Al Qaeda was born of Zawahiri's vision and bin Laden's money.

Bin Laden himself emerges as an enigmatic character. Deeply pious, at once grandiose and introverted, he's a man who made sure Al Qaeda members had health insurance and vacation time, yet who was basically incompetent as a businessman and a field general (his one battle against the Soviets was a fiasco). His greatest asset, however, was his zeal for jihad, which attracted the kinds of single-minded professionals, like Khaled Sheikh Mohammed, capable of carrying out 9/11 on their own.

Through it all, America slept. The Looming Tower tells that story, too, with the same sense of urgency and suspense, though we know the ending. A monumental piece of research, the book is the result of more than 600 interviews. Ultimately, it represents what we should have known then; it's the least our leaders can do to try to understand their enemy now.

-Chris Parris-Lamb