Just south of Grand Island, Neb., along Interstate 80, stands "Erma's Desire," a large abstract sculpture with steel spires pointing in every direction. It was controversial when it was unveiled in the early 1970s, opposed by people who thought it a blemish on the flat Nebraska landscape. For John Janovy Jr., though, "Erma's Desire" symbolizes a windblown liberty of mind compatible with the prairie he loves. The strongest and loftiest steel beam of the sculpture points insistently westward, toward the bleak but inviting horizons of Keith County, Janovy's spiritual home.

For the last eight years Janovy, a professor of biology at the University of Nebraska, has conducted field studies at a camp in Keith County, nestled against the bluffs and sandhills of the southwestern corner of the state. In 1978 he covered this territory in his "Keith County Journal," an impressionistic and likable account of the snails, birds, fish and people of the region. He then took a year's sabbatical to follow a single sandpiper in its annual migration from Nebraska to South America and northward again to Canada. He could pursue the bird, as he tells us in his second book, "Yellowlegs" (newly issued in paperback), only as far as the Gulf of Mexico; he drove his used Mustang right into the surf and, unable to go any farther, left it there.

In his new book, Janovy has returned with his summer students to Keith County for more observations of nature and musings on life. Far from going to the same well once too often, though, he has produced his best book. He has reined in his previous excesses of tone and occasional wantonness with language and developed instead a more controlled voice and a surer grasp of his subject.

Janovy is trained to look through a microscope at tiny forms of animal life, but he can also cast an acute eye on the human species. In one illuminating essay he writes of the Corfields and Packards, two independent but surprisingly sophisticated ranch families who would be reluctant to set foot in a city even if they had to. When Janovy returns from his visits to the ranchers, he takes with him "impressions of the isolation, the estrangement, the brazen self-reliance, that very pluck of the coyotes they hunt, the audacity to confront the elements that sweep down out of the north."

One of Janovy's appealing traits is a relaxed earthiness that allows him to cultivate the friendship of some of the quirkiest people in the West. Usually he seats himself at some out-of-the-way bar -- this time a place called the Sip 'n' Sizzle -- and waits for something interesting to happen. And sure enough, it isn't long before he meets Lonnie Paul Dinkle, a boastful drifter who cajoles Janovy into letting him work at the Keith County camp in return for a place to stay.

Lonnie Paul proves to be a remarkably interesting and resourceful character, capable of picking a lock and of repairing the power company's imposing electricity-generating windmill with nothing but his pocketknife. An adventurous ne'er-do-well, he nonetheless asks probing questions about biology that Janovy's best students had not thought of, and passes on a philosophical appreciation of the plains. Looking off into 15 barren miles of sandhills, he says to Janovy, "Doesn't that just give you some feelin' inside you can't describe? Don't you just feel you need what you're seein' out there?"

When Janovy turns his attention to animals, he shows a rare gift for making science palatable and for applying its lessons to other spheres of life. Between the lowly killifish, only two inches long and not even good as bait, and the South Platte River he sees "a relationship always true through flood and drought, feast and famine, the turbulence, meandering, unfaithfulness, shallowness, undercutting, uninhibited whoring times. Suddenly, I think, a species of fish that could help us learn how to survive those kinds of times might have some economic value after all." Feeling the eyes of a cliff swallow on him as he seines for fish, Janovy wishes he could transfer the bird's intensity of curiosity to his own students. When an oriole sings in response to a banjo on a country-music tape, he hears in the two sounds the common rhythm of nature.

The faults of "Back in Keith County" are minor in comparison with the pleasure it affords. An editor should have caught some spelling and other minor errors, but the strength of the narrative overshadows these lapses and the forced slang that Janovy occasionally interjects. Several of his drawings and watercolors illustrate the book.

All in all, Janovy has given us a superb example of nature-writing and of life in the Great Plains, perhaps surpassing such admired works in the genre as Aldo Leopold's "A Sand County Almanac" and William Warner's "Beautiful Swimmers." Janovy takes us on a journey of intellectual serendipity, deriving extraordinary thoughts from ordinary circumstances.