THE EARTH IS ENOUGH Growing Up in a World of Trout and Old Men <i> by Harry Middleton (Simon & Schuster: $18.95; 269 pp.) </i>

Harry Middleton’s vivid and moving memoir is part autobiography and part homage to the two old men who taught him to love the outdoors. In a few brief but sure strokes, Middleton sketches his family circumstances, with a stunning description of a tough military father. Near the military base where Middleton’s father is stationed on Okinawa, one of the author’s schoolmates is killed by an old hand grenade the boys find in a creek bed. The young Middleton is immediately packed off to live with his grandfather and granduncle on the family farm in the foothills of the Ozarks. On the bus trip across the States, the boy fears he is being “handed over to tobacco-chewing, brain-damaged hillbillies.”

Instead he finds two old eccentrics with whom he feels instantly at home. Grandfather Emerson and Uncle Albert own a tract of miserly “hardscrabble” land, but they revel in their wilderness of ancient, tenacious trees and wild game. Their lifeblood is liberty and solitude, the possibility of hunting and, most of all, of trout fishing in Starlight Creek. The old men raise vegetables but no animals because, whereas tomatoes are never in a hurry, animals have a habit of requiring attention just when the “trout were rising or something more interesting or illuminating was happening up in the mountains or deep in the woods.”

The farm is in fact so unproductive that a state agricultural agent calls it “an agricultural disgrace.” The scene with the agent, in which the old men can barely conceal their pride at having kept the land so wild and pristine, contains their whole philosophy. In answer to the agent’s advice to cut down the useless trees and plant valuable pines, Emerson protests: “Certainly the world isn’t experiencing a shortage of telephone poles.” Instead he asks for advice on how to preserve the trout’s environment. Trout are “finicky, civilization upsets them. They’d rather die than have any part of it.” Albert then invites the fellow to go fishing in a perfect place where there’s a sly old trout, adding: “Of course, if you hook him we expect you to do the decent thing and let him go. If a man is careful and lucky, some of life’s thrills can be experienced more than once.” As the agent withdraws in fury, he rebukes them: “Goddamn old hippie communists. Men your age, too. You ought to be ashamed.”

In the old farm house that “tended to embrace the practical rather than the needless, the theoretical, dispensable or the visionary,” there are no modern conveniences except a radio, so that Albert can play his Hohner harmonica along with a weekly blues program from Memphis. Another indispensable item in their life is books: hundreds of them. In the evenings and in foul weather, the old men attend Roman orators, converse with Mark Twain, are aggravated by Evelyn Waugh. When it appears that the young Middleton is bitten as hard by the bug of writing as of fishing, they build him a desk, and eventually, a chair, straight-backed and plain like everything else in the house. “No writer writes, I hear tell,” says Emerson, “unless he’s uncomfortable with something, even if it’s just a chair.”