'The Worst Hard Time' nimbly chronicles tragedies of the Dust Bowl

Egan anchors the story on three towns in Texas, Oklahoma, and Colorado. Year by year, you get to know young couples struggling to keep their children alive, a resolute newspaperman, a cowboy father turned broken rancher, and high school kids barely hanging on to their youth.

Massive land mismanagement and a few years of drought transformed the Great Plains from waving fields of prairie grass into constantly shifting sand dunes that blocked roads, buried fences, and smothered gardens. The sand blew into the eyes and mouths of cows, blinding and suffocating them. It blew into the lungs of children and adults, creating a new, deadly illness: dust pneumonia, which carried a cough so brutal it could crack ribs. It drove some people mad.

Illuminating these hidden lives serves to strengthen the larger story of the Dust Bowl. Egan nimbly moves his lens between macro and micro, balancing hard data and national conditions with portraits of people you come to care about.

As with many economic catastrophes, the seeds of misfortune sprouted in a giddy fashion; this time in the lush 1920s, when prices skipped out of control and even the skies over the Great Plains bestowed above-average rain for much of the decade. The First World War generated a global need for wheat. Great Plains ranchers became farmers, and people poured into the region to grab cheap land and big profits. The latest technology helped them meet demand: Powerful tractors could plow staggering amounts of land per day.

Never mind that this land of ''high wind and low rainfall" was never meant to support large farms. The best plant for the region is hardy prairie grass, which thrives in the arid climate and can withstand the strong winds. For centuries prairie grass had nourished vast herds of bison, and more recently had sustained enormous cattle ranches. Most important, it had held the dry prairie soil in place.