Many years ago I flew from Bangkok to Kathmandu. (2) My flight passed over the Bay of Bengal and shortly thereafter I watched out the window as a low rise of mountains took shape on the northern horizon. It was the end of the monsoon season and humidity filled the air above the Indian plains, obscuring the range so that I saw only a bluish smudge of relief where it stood against the sky. When we got closer, though, the giant snow peaks materialized-Kanchendzonga, Makalu, Everest, Cho Oyu and Annapurna-like a row of tiny sharp white teeth. They floated magically above the haze, ephemeral, as if at any moment they might dissolve into it. It was a splendid sight flying into the Kathmandu Valley thirty years ago. Little had changed in the preceding centuries and the colorful history of the kingdom was evident in the landscape. Traditional features still dominated the scene: stucco-and-thatch homes, cattle in pasture, meandering rivers and farm lanes that intersected according to the lay of the land, spiraling rooftops and ornate facades of imposing monasteries, all composing, like the pieces of a puzzle, an imaginary and far-off place. Prayer flags fluttered wildly above a golden temple so that it appeared to be caught momentarily in flight. A medieval town, surrounded by rice paddies whose watery surfaces caught the sky and passing white clouds, appeared to float in a lymphatic prism. Plumes of smoke hovered above a cremation grounds before drifting toward a bamboo grove that encircled the King's palace. The cultural monuments popped into view, one by one, as if cut from the illustrated pages of a storybook. In the background were the icy peaks. Such fanciful images of the Himalaya are pleasing and self-evident, and a delightful abstraction, but they don't, of course, fully describe the place; they're rendered, after all, from the view out the window of a passing jet airliner. My later explorations sketch more complex pictures of the mountains, showing them to be places of struggle, contradiction, and change as well as places of harmony and timelessness, degradation and beauty; places, after all, of human circumstance. Nonetheless, I retain in my mind that initial birds-eye view of the Kathmandu Valley-its luminous qualities laid the foundation for much of my later inquiry into the nature of life in the Himalaya, encouraging me to not merely observe and document, but imagine the place. The scale of the mountains is enormous and their scenery is spectacular. For once, the glowing superlatives used to describe a place are entirely appropriate. The Himalaya contains Earth's highest mountain (Mount Everest, 8,850 meters, 29,035 feet), deepest gorge (Yarlung Tsangpo Gorge, 5,382 meters, 17,657 feet), and wettest place (Cherapunji, 10,871 mm/year, 427 inches/year). It's a trove of natural wealth, with more than ten thousand native plant and animal species, and a biodiversity center of global significance. Caught in its altitudinal grasp is a plethora of climates so diverse that a flatland equivalent would require traveling across the planet's surface from tropical to polar latitudes. Geography thus bestows upon the Himalaya an extraordinary presence. Such attributes taken alone, though, might threaten to reduce the Himalaya to a geographical oddity, as if its physical qualities were merely a hyper-attenuated architectural feature of the planet's surface, were it not for the story of humankind in the mountains. In fact, the rugged setting is most extraordinary precisely because it has been settled by people for many generations. Today, more than fifty million persons live in the Himalaya and contribute enormous human prospect to it. Their settlements have altered the very shape of the land, and their societies weave an astonishingly rich fabric of life that drapes the mountains in the shimmering folds of tenacity and enduring human purpose. Cultural miscegenation greeted me when I first disembarked from my flight to Kathmandu. …