The events of September 11, 2001, have spawned a series of books that analyze the causes and consequences of international terrorism. Historians and analysts consider the events as marking the "Year Zero" because they indicated the start of a whole new type conflict in which foot soldiers and conventional warfare are obsolete. Can 9-11, as it has become known, be viewed as the beginning of a new war against the West using unconventional methods to strike at some of the world's most powerful countries? Historians, scholars and political scientists have been trying to explain the events. But history is full of examples of unorthodox acts of war. Christopher Coker goes back to ancient times, when Greek philosophers and warriors devised the strategy that set the course for future warfare and lay the groundwork for military strategists and politicians to build upon. But nothing in history quite resembles the attacks on the World Trade Center, when fundamentalist Muslims, acting on faith and sacrificing their lives, shocked the world with their bold actions, using an airplane as a rocket against a civilian target and killing thousands of people. Coker examines various concepts of warfare, from the ancient to the modern. He includes World War II, during which "kamikaze" pilots of the Japanese imperial army struck at the might of the US Navy in the Pacific and at Pearl Harbor in December 1941.

Among the great war strategists of the ages is the revered Chinese philosopher Sun Tzu, who wrote "The Art of War" centuries before the birth of Christ. Historians place the writing at about 500 BC, about the same time the writings in the "Tao Te Ching" (another famous text that spells out Taoist principles) were composed. Both texts have been studied for millennia by Chinese military leaders. One key teaching in these writings is that the object of war is not to impose one's will, but rather to undermine the enemy's will.

"Attack the strong through his strength," one teaching says. It means that one should not meet strength with strength, which is the Western way. "A concept such as the 'culminating point', the point at which the strength of an enemy tends to dissipate through over-extension occasioned by success, may be new to the West but not to China," Coker writes. Not using strength to fight strength seems an unorthodox way to fight a war. Since 2001, the concept has been known as "asymmetric warfare" and is often compared to water. According to Taoist concepts, water is formless and so is war, Coker says.

"Outwitting and outmaneuvering an enemy and in the end surviving is everything," the author explains. Two colonels in the Chinese People's Liberation Army wrote a book titled "Unrestricted War," in 1999 acknowledging that a weak army cannot use conventional means to fight a strong country like the US, but must use unorthodox means instead. Coker uses the example of that book to explain that the teachings of old masters are well received by present-day military planners.

Coker explains the military theories behind conflicts in India (which were formed in part by the passage of Alexander the Great), the war between Russia and Chechnya, the Middle East, Africa, and Latin America. The concepts found in these regions are described as 'non-Western' as opposed to the 'Western way' promoted since the 17th century when Western countries colonized the world. Coker says the Western way of warfare has remained dependent on the technology of firepower and has continued to rely on a concept of discipline and decisiveness adopted from the Greeks and Romans. Today the Western way is to allow human beings to utilize technology to make war.