Fallingwater is about four hours' drive from Washington, a beautiful trip through the mountains of Western Maryland and the Laurel Highlands of Pennsylvania in countryside that has been settled but not yet spoiled. At journey's end you park at the Visitor Center, then pass through what Franklin Toker calls "a forest of such virginal purity that we walk through it as though enchanted." At the end is the house itself, suspended over the creek called Bear Run:

"Visiting Fallingwater has only a little to do with architecture and engineering: the quality we perceive here is essentially spiritual. Nearly everyone falls under the spell of the house, recognizing in it the most serene building we will ever encounter. . . . We realize when we see the brooding concrete masses alternating with the hand-hewn stone walls that it is not the modernity but the antiquity -- even the eternality -- of Fallingwater that enthralls us. The rocks that are so much a part of the house will be here forever. The water that animates it will never stop flowing. And despite its daredevil engineering, Fallingwater will never fall down -- although it threatened to, a few years back."

Indeed it did, which is why "forever" and "never" should be used with a bit more caution than Toker does in those sentences. But about Fallingwater's breathtaking beauty and its deeply spiritual quality there can be no doubt, at least in my mind. I have been to Fallingwater three times, each trip a pilgrimage, each even more rewarding than the previous one. I am not given to spirituality and am not especially fond of most modern architecture, but I am far from immune to "the deep spirituality that people intuit in the house" and agree that because Fallingwater's "key allusions are to nature. . . . Every visitor and viewer seems to find in Fallingwater some echo of his own culture."

Designed by Frank Lloyd Wright for the Pittsburgh department-store owner Edgar J. Kaufmann, Fallingwater was built in the mid-1930s and became a popular sensation in the years following its completion. A vast amount of literature has been devoted to it, and numerous myths have accumulated around it. Toker, who teaches at the University of Pittsburgh and is a past president of the Society of Architectural Historians, makes in Fallingwater Rising a determined effort to separate myth from reality, to set the record straight about such matters as who was the real inspiration behind the house, how quickly (or slowly) its design formed in Wright's mind, how firm was Wright's grasp of the engineering challenges his design posed and what brought about the great burst of attention that greeted the house.

Toker's answers to these questions, all of which are persuasive, are: (1) It was Kaufmann himself, not his aesthetic son Edgar Jr., who engaged Wright's services, heartily approved the revolutionary design and saw the project through. (2) Contrary to the legend that Wright sketched out the design in a few hours, he worked on it for months before wrapping it up in a grand final spurt. (3) Wright's grasp of engineering was shaky, and the house as built, with its magnificent cantilevered terraces jutting over Bear Run, was almost instantly imperiled. (4) The acclaim that rained down upon the house was carefully engineered, probably with Kaufmann himself as master puppeteer but with important supporting roles played by Architectural Forum, Henry Luce's Time-Life magazine conglomerate and the Museum of Modern Art.

All of this will be of interest to Fallingwater devotees, but even some of these may feel that Toker goes on too long, repeats himself unnecessarily, and supplies more detail in certain instances than is really necessary. Fallingwater Rising is a good book, but it would be a better one were it, say, a hundred pages leaner. Still, not merely does Toker tell what may well be as close to the truth as we'll ever get about the building and boosting of this singular masterpiece; he also provides something of a synthesis of existing scholarship and journalism as well as a fascinating analysis of the relationship between architect and client:

"It is a truism that an architect needs a client more than does any artist, since an architect without a client can produce nothing. But the architectural client will always be special because she or he has a real need for a house or an office tower, not merely the intellectual interest a patron might take in a painting. . . . Over a period of twenty years E.J. Kaufmann and Frank Lloyd Wright seduced each other, loved each other, hated each other, and betrayed each other, now with the one getting the upper hand and now the other. It is hard to imagine the often-buffoonish Kaufmann as the prime client of Wright's career, and still harder to take in what Kaufmann's support did to launch Wright on one of the great comebacks in art history. . . . E.J. Kaufmann did not create Fallingwater, but it speaks volumes for his courage and shrewdness that when Fate gave him a chance to sponsor an architectural wonder, he seized it."

Each man, Toker argues, brought a deep need to the collaboration: Wright to restart a career that had foundered, Kaufmann to assert himself against "the anti-Jewish snobbery of Pittsburgh." Of Wright so much is known that no further word is necessary. Kaufmann, by contrast, has receded into obscurity, eclipsed, in the minds of many, by his son and only child. He was a canny merchandiser and publicist, a lover of art and architecture, a "partner in a hollow marriage" who collected mistresses as avidly as he collected art, a tough bargainer who knew when to stand firm and when to compromise.

The Kaufmanns' marriage may have been empty, but both E.J. and Liliane did more than go through the motions. They were partners, albeit unequal ones, in Fallingwater, which "was no mere building project" for them: "it was the central fact of their lives." The "main dividend the Kaufmanns sought from Fallingwater was respect," and they earned it in generous amounts. They didn't join Pittsburgh's best clubs (though Edgar Jr. eagerly did), but after Fallingwater the city's elite had to accept them as equals at the least, perhaps indeed as superiors.

In many ways the most interesting aspect of Fallingwater Rising is the long penultimate chapter devoted to Edgar Jr. He "made his mark as an important American aesthete of the twentieth century," but he was "a tormented soul" afflicted in four ways: "his father E.J., his mentor Frank Lloyd Wright, his homosexuality, and his being Jewish." In creating the legend that he, who had briefly (and unhappily) been a student of Wright's, was the real driving force behind Fallingwater, he appears either to have deluded himself or to have lied, but in the three and a half decades that Fallingwater was his own he maintained it with care and (for the most part) architectural integrity. When, in October 1963, he gave Fallingwater to the Western Pennsylvania Conservancy, he assured its preservation and made it accessible to a grateful public.

There is much more in this book -- as noted, rather too much more -- including some interesting speculation about how the interior plan of Fallingwater "charted the dynamics of a dysfunctional family" and how the particular popular mood of the Depression made the country so receptive to the house. It will be interesting to see how the architectural community, which has tended to take sides in the dispute over which Kaufmann was the real force behind the house, will respond to Toker's disclosures. Most readers, though, will simply be inspired by Fallingwater Rising to visit the house -- you perhaps for the first time, I for the fourth. •

Jonathan Yardley's e-mail address is yardleyj@washpost.com.