America is at war with an elusive, adaptive, and ruthless enemy. It is an enemy unlike any faced in the past; one that eschews an identifiable uniform, has no state of its own, does not abide by Western rules of warfare, hides amongst civilian populations, can attack U.S. targets at home and abroad, cannot be deterred, and relies on the use of terrorism and propaganda to further its cause. This enemy is al Qaeda, an organization that has emerged as the leader of a global jihadist movement. It uses off-the-shelf technology, the interconnectedness of the increasingly globalized world, and the freedoms of the Western world and the grievances of the Middle Eastern world to advance a new social order based on a seventh century religious ideal. Despite lacking a state from which to draw resources or raise an army, this committed group of religious zealots has been at war with the United States since the 1990s. In that time, they destroyed two United States embassies, attacked, and nearly sank, a United States Navy warship, and inflicted the worst terrorist attack on American soil in U.S. history. In addition, they have survived nearly nine years of the Global War on Terror (GWOT) with the United States and its many allies. Likewise, since September 11th, 2001, its members conducted, assisted, or inspired successful attacks throughout Europe, Africa, Asia, and the Middle East. Recently, they came within a breath of destroying a passenger jet over Detroit on Christmas Eve, 2009. In many instances, al Qaeda maintained the initiative against its foes, adding to their appearance of strength and competence. This is a considerable feat considering the military and economic might of the United States and its allies in the late twentieth and early twenty-first centuries. The central question at this time must be this: What has prevented the United States from decisively defeating al Qaeda? Why, after years of great effort and expense, is there still no end in sight? This monograph asserts that America cannot defeat an enemy it does not understand. Specifically, an incomplete understanding of the enemy and the operational environment is critically hampering the efforts of the United States and its allies in the GWOT. In light of this assertion, it explores and broadly examines the operational environment of al Qaeda and the Arab Muslim world on which al Qaeda depends. With the intention of reassessing the enemy and its environment, the paper is motivated by the words of Sun-Tzu, who wisely called warfare "the greatest affair of the state, the bases of life and death, the Way (Tao) to survival or extinction. It must be thoroughly pondered and analyzed. . . . [t]he victorious army first realizes the conditions for victory, and then seeks to engage in battle. The vanquished army fights first, and then seeks victory." Whether America is to be victorious or vanquished depends on its ability to realize the conditions for victory before engaging in the battle. Obviously, the GWOT cannot come to a full stop while military planners and policymakers reconvene to analyze the enemy. Yet it is important to take a step back and reevaluate, refocus, and learn. America cannot just "fight first...then seek victory." This monograph explores the topic of America's war against al Qaeda. It strives to shed light on areas of understanding that planners potentially overlooked when the United States first designed its response to the 9/11 attacks, many of which continue to plague America's efforts to defeat al Qaeda today. Its purpose is to inform, not to argue in favor of one policy or another. After all, any proposed policy or strategy should spring from a fundamental understanding of the situation and the key players involved. This paper is a small step toward achieving that understating.