Into thin air

Or so the story goes. As Childs explains it, no one really knows what happened to the ancestral tribes of the Southwestern canyons now lumped together as the Anasazi. Their disappearance has captivated modern explorers, professional and casual. It is a mystery pieced together from tree-ring patterns in fallen roof beams, pottery shards, human bone fragments unearthed by archeologists and hikers (one of them a Boy Scout whose flashlight fell down a hole). Any number of solutions to the mystery could be true.

In "House of Rain" (the title refers to the dwelling of an ancient god), Childs does not undertake to solve the mystery or referee among bickering archeologists. Instead, he sets out to ramble through the ancient canyons with their crumbling kivas, to linger over the pottery shards and human bones and to interview the archeologists who have devoted their lives to understanding these ancient people whose very name is in dispute. "The word 'Anasazi' was crafted by the Navajo, who in the 1800s were paid by white men to dig skeletons and pots out of the desert," Childs writes. Long thought to mean "old ones," it in fact translates as "enemy ancestors," which naturally angers the Anasazi's descendants, who include the Hopi and Zuni tribes. Midway through the book, Childs simply abandons the appellation, which, he explains, "had grown fainter with every mile I had traveled."

Childs' journey begins at Chaco Canyon, in northwestern New Mexico. From there, he treks to Utah and then south again, to the ancient northern Mexico town of Paquime (now Nuevo Casas Grandes), where a later civilization much like the Anasazi flourished. Sometimes, Childs travels with his wife and their baby son, allowing him to ruminate on the intricacies of tending to a toddler on the trail. Sometimes, he travels with friends, with whom he negotiates flash-flood channels and vaults over crevasses. It is a somberly focused, physical trip, and you learn at the outset just how precisely he will describe it. ("At the river I untied the canoe's bowline, stepped in, and swept the paddle into the water, setting a wake across a mirror of stars.")

You can open to almost any page in "House of Rain" and find an evocative line of prose. Every object is active and vivid: Tires "gobbled at paprika-colored sand"; flies land "to sip sweat off our forearms"; wind "scrapes and hisses across the red, bare earth." Whether you savor such tactile accounts as Childs rousing himself from his sleeping bag or setting his baby's "diaper-padded bottom" on the back of a truck depends on how much time you have and how badly you want to solve the puzzle of Anasazi history. But if you decide to hurry to the end of this lovely book looking for answers, you will be disappointed. Childs has done casual scholars of the prehistoric Southwest a great favor by compiling so much information so fluidly in a single volume; he has not, however, sorted it in a way that makes sense of the ancient peoples' end.

What happened to the great civilizations of the Southwest that flowered so exquisitely and flickered out so abruptly? In addition to the Anasazi, there were the Hohokam, who built complex irrigation systems near what is now Phoenix. And then came the Salado, "a massive cultural convergence based in east-central Arizona, where migrants collided with numerous indigenous heritages that had been in place for centuries." (Like "Anasazi," the name refers to an epoch rather than a unified tribe.) At Paquime, a vibrant people kept birds for sport and food, built great houses and watered their fields. By the end of the 15th century, some 200 years after the disappearance of the Anasazi, all these indigenes were gone. When the Spanish arrived in the 16th century, they "probably met with only small, scattered populations, feeble resistance to thundering columns of conquistadors clad in leather and steel."