Americans love Australians. And with what good reason. They are so like us. They, too, were settled in considerable part by British convicts; they, too, destroyed many of their indigenous population; they fought gallantly beside us in World Wars I and II and in Korea. They warmly gave visiting Americans from the Vietnam war the feeling that at least one of our traditional allies liked us and supported our foolhardy venture. Indeed, if Australians ever cease loving us, we will have become, finally, unlovable.

Because of our love affair with Australia it is painful to observe that the Australian beef we get is fit mainly for hamburger, the wines mediocre and the books uneven.

In "The Thorn Birds," with which "Inherit the Sun" is being compared, we got a 692-page saga of procribed love, explicit sex, death, religious conflict . . . well, all the ingredients we expect to get from a saga in the "Gone With the Wind" tradition. "Inherit the Sun" is also a hefty book, and its physical design booms out "epic." Coward, McCann & Geoghegan have produced a laudably beautiful volume the likes of which we seldom find anymore, with colored end papers, the author's signature gold-stamped on the cover and a costly two-tone, cloth-backed binding. But unhappily, the content is not up to the wrappings.

Its beginnings are auspicious. We are introduced to the first of the three generations, which seem to be requisite in prairie, jungle, cotton plantation and drawing room sagas. They are Beth Brennan, a citified schoolteacher who takes as her second husband "Murranji Mac" Carlyon, a dashing catle drover. They settle in Australia's outback.

In that vast land of aborigines, wilderness, crocodiles and grazing acreage they raise a family whose star, and the book's main character, is "Big Red" Carlyon, very much his father's swashbuckling son. "Big Red," in turn, through an unconventional (and unconvincing) liaison with a woman doctor, sires and raises a daughter, Alison, who is the quintessence of her father and grandfather.

The time frame is from 1896 to 1974 and the sense of leisure, even grandeur, with which the book begins is immediately absorbing. The white men in the Northern Territory are rough, generous, resourceful. The aboriginal blacks are mysterious, capable and -- given their distance in time and their foreignness -- exceedingly well-drawn by Maxwell Grant, the journalist author.

The early action is cleanly described, brutal without being brutish, sensual without being sexy. For a hundred pages, all the elements unite to promise us an absolutely marvelous novel: exotic, broad and intense.

For openers, Beth Brennan and her nincompoopish first husband are abandoned by their Afghan camel driver as they trek across the Australian desert. The husband dies of exposure. She remarries and her new spouse, "Murranji Mac," takes dramatically satisfying vengeance by kidnapping the Afghan and leaving him, too, in the desert. There is a sensational and pertinent barroom fight, and a four-month cattle drive ranging over a thousand miles. There is "Big Red's" birth on a bed of bark and leaves under a hurricane lamp just as Beth reaches her new homestead, with an aborigine as midwife.

Unaccountably, with an overture so rich in fresh themes and variations, the work saga when it gets down to business. There are still good scense: crocodile hunts, World War I action, "Big Red's" desperate ride across the desert to save a baby from typhus, and, appositely, "Big Red's" lover's vain attempt two decades later to cross a much shorter stretch of desert by car -- proving that the outback demands its toll even in modern times.

Overall, though, the sense of expensiveness is gone. Just as the back country constricts, so do the book's spaces. The characters become myriad and commensurately shrink as distinct entities. And because this is a novel of time, place and character, not of plot, when the characters diminish, the book is flawed. Without its third leg -- character -- the easel threatens to collapse, the whole picture with it.

Adroitly, the author tries to prop it up by substituting action, and in part he succeeds. But it is a different book now. And while earlier we could forgive such stylistic sloppinesses as "big, big man," "thick, thick black hair," "very, very bad," they now annoy, "Very, very blond," "old, old" furniture, "tiny" twice in the same paragraph to describe a woman, the overuse of "cheeky," repetitions of facts, while individually only niggling errors, become aggregately a serious fault.

All this said, the book is not a failure. It is merely a half success. Its intent and execution remain serious. It is well worth reading.

But we have come to expect much from British "colonial" writers, whether in terms of spectaculars like "The Thorn Birds" or in such eminent artists as Doris Lessing and Robertson Davies, Alan Paton and Nadine Gordimer. And it hurts to see a talented Australian like Maxwell Grant fall short when Americans are so predisposed to wish him well.