Best New 'Man Versus Wild' Books

Why do we farm deserts and plunder wild habitats, if the long-term effects are so regrettable? Two new books, David Quammen's 'Spillover: Animal Infections and the Next Human Pandemic' and Wade Davis' 'River Notes: A Natural and Human History of the Colorado,' investigate that drive to alter the world we live in – and look at what we can do now to deal with some of the repercussions.

In the summer of 2000, science writer David Quammen was sitting by a campfire deep in the central African wilderness when the conversation turned to the Ebola virus – two of the men around the fire that night had survived a horrific outbreak in 1996. In the early days of the virus, they said, they'd come across a strange sight: 13 gorillas lying dead in the forest beyond their village.

"I never got that image out of my head," says Quammen. "A pile of 13 dead gorillas, representing the fact that this horrible disease that kills humans is also killing gorillas and chimpanzees, and living somewhere in the forest, undetected in a reservoir host." These kinds of "spillovers," in which an intrepid pathogen makes the leap from animal to human, account for roughly 60 percent of infectious diseases, including bubonic plague, SARS, West Nile virus, influenza, and AIDS. "There seems to be this increasing drumbeat of disease emergence," says Quammen, "particularly viruses. The question is: Where are they emerging from, how are they emerging, and why more so now? And, of course: What does the next big one look like, and what can we do about it?"

'Spillover' is Quammen's hunt for answers, as he follows the scientists cracking viral codes and tracking down bugs before they go global. It's part forensics-adventure story (trekking through virgin forest in the Congo basin, netting for infected bats in Bangladesh), part history of pandemics (he stitches together, for the first time, the full story of the emergence of the AIDS virus, which scientists now believe jumped from a chimpanzee to a hunter – circa 1908).

One thing is certain: Modern life is a boon for contagious disease. "Humans are evermore present on the planet, pushing into new places, including the tropical forest," Quammen says. "Cut down a tree and things fall out, including viruses." But the upside to that global interconnectivity, of course, is awareness – as viruses zip around the globe, so does information. "As soon as a child coughs in Vietnam and tests positive for bird flu," says Quammen, "the CDC hears about it, and they get on a plane and go help. The fact that there was good information passed around the world so quickly made it possible to contain the SARS outbreak at the point where it had killed 700 people rather than 7 million."

In 'River Notes', explorer Wade Davis looks at the ways in which human intervention has changed the American West, in a beautifully concise history of the Colorado River – from the volcanic heyday of the Grand Canyon's formation to today's river, the most engineered on Earth.

Eighty years ago, the Colorado made its way to the sea through a vast river delta the size of Rhode Island – a paradise of wild grasses, emerald lagoons, boar, jaguars, bobcats, porpoises, giant bass, and flocks of birds so dense they reportedly darkened the sky. These days, the river barely reaches the sea at all, its flow diverted along the way to support farms, cattle, and millions of people in Las Vegas, Tucson, San Diego, Los Angeles, and Phoenix.

In the mid-1800s, just as the Mormons were setting down roots on Great Salt Lake, the American West was undergoing a transformation – at least in the popular imagination – from the Great American Desert to the nation's future breadbasket, a sleeping agricultural megasource that needed only to be awakened by the plow. (As Davis points out, the absurd notion that wherever earth was tilled, rain would follow was considered solid science well into the 19th century.) When the rains didn't come, exploiting the Colorado became an inevitability.

The Hoover Dam was the first to go up along the river – a marvel of American engineering, and in its day, the largest structure ever built. Dedicated in 1935, during the depths of the Great Depression, it offered a much-needed boost to national morale – and, unfortunately, inspired the eventual construction of two dozen more dams.

"I wanted to look at how this river got compromised, given its importance in the American imagination," says Davis, who made his first trip down the Colorado in 2006, as part of a film with Robert Kennedy Jr. In 'River Notes', Davis takes the reader on that expedition, from shove-off at Lees Ferry, Arizona, into the canyon's notorious rapids. He alternates episodes of nerve-racking whitewater with the geological and cultural history of the region – and, finally, offers an enticement to restore the delta. "The core of the delta could be regenerated with a trivial amount of water," says Davis. "What a symbol of hope that could be for everybody."