From its source in the Qinghai-Tibetan Plateau, the Mekong River flows 2,600 miles (4,180 kilometers) through China, Myanmar (Burma), Laos, Thailand, Cambodia, and Vietnam, from which it empties into the South China Sea. The longest river in southeast Asia, it is vital to the daily lives of the region's inhabitants. In fact, one in every three people in Laos, Thailand, Cambodia, and Vietnam live in the Lower Mekong River Basin. In vastly divergent ways, the lives of many of these people are interwoven with the uneasy legacies of war, colonialism, and modernization. Violence, poverty, displacement, ecological crisis, and the fragmentation of traditional cultures are endemic. At the same time, these social realities, and the life-sustaining resources of the "Mother of Rivers," as the Mekong is known in Laos and Thailand, harbor the potential for transformation.

The Mekong travels through vastly different landscapes. At its source in the Qinghai-Tibetan Plateau, the Tibetans call it Dza Chu (Water of Stone). The river then surges 1,000 miles south and east through Yunnan Province, China, where it is known as Lancang Jiang (Turbulent River). Here, whitewaters and rapids, rushing through gorges as deep as the Grand Canyon, render it largely unnavigable. Below China, however, as it streams through the Golden Triangle, where Myanmar, Laos, and Thailand meet, it becomes calm. It subsequently flows gently south and east through Laos. Just below the Cambodian border, it reaches the Khone Falls, a series of falls 7 miles (11 kilometers) long, above which the river splits into numerous streams encircling small islands in an area known as Si Phan Don (Four Thousand Islands). In Cambodia, at a confluence the French called Quatre Bras (Four Arms), the Mekong and the Tonle Sap (Great Lake) River join, and their waters then split into the Mekong and the Bassac. These two rivers flow side by side through southern Vietnam, where they form the network of tributaries the Vietnamese call Cuu Long (Nine Dragons).

Just as the Mekong flows through vastly different landscapes, it connects vastly different communities. Most live in the Lower Mekong River Basin in Southeast Asia, where the final 1,000 mile (1,600 kilometer) stretch of the river is navigable. In this region, there is a saying that the Lao people live near the river, the Cambodians live on it, and the Vietnamese live in it. This saying not only underscores the river's importance in the region, but also suggests the divergent relationships people have with it. Its seasonal monsoons and floods establish the rhythm of daily life, and festivals such as the Rocket Festival and the Water Festival mark the seasons' ebb and flow. Farmers cultivate more than four hundred varieties of rice, as well as other crops, and fishermen catch numerous species of marine life. Merchants sell their goods from floating markets. And nestled against the river's banks are small fishing hamlets, as well as vast urban centers, including Phnom Penh, the largest city on the river, with a population of about one million.

The Mekong tells a story whose chapters read like palimpsests, each one legible over the others. Strategically located at the crossroads of Asia, the area is a rich admixture of indigenous and foreign cultures. Some of the earliest known agriculture and metalworking in the history of the human race are found here. In 2500 B.C.E., the first canals in the Mekong Delta were built. After the death of the Buddha in the fifth century B.C.E., monks from India traveled the river, bringing Buddhism, still the region's main religion. In the twelfth century, the world's largest religious complex, Angkor Wat, which covers 156 square miles (404 square kilometers), was built: waters from the Mekong's tributaries were used in the complex's moats to represent the oceans surrounding the temples. In the nineteenth century, Angkor Wat was rediscovered by French explorers looking for a water route to China, who tried and failed to find the river's source. The twentieth century was marked by both upheavals and reorganization. In 1957, countries in the region founded the Mekong Development Committee to harness the river's resources. In the 1960s and 1970s, the Mekong Delta was the site of some of the most violent episodes of the Vietnam War. These events constitute a minute fraction of the complex history of the river and its people.

Today, the rich and turbulent legacy of the Mekong leaves the people who depend on it with both challenges and the resources they need to build for the future. As the countries of the region have modernized and industrialized, they have turned to the Mekong. The use of chemical pesticides and fertilizers to increase agricultural yields has polluted the river. Damming projects providing electricity have disrupted its unique ecology, forced the relocation of thousands, and threatened traditional farming patterns and ways of life. In addition, modern warfare has scarred both the river and the people. During the Vietnam War alone, the river was booby-trapped with mines and polluted with Agent Orange and napalm; thousands of tons of bombs were dropped on Laos, Cambodia, and Vietnam. Nevertheless, the life-sustaining "Mother of Rivers" offers hope for the future of the people who depend on it.