ARCHITECT Richard Neutra often said that he saved marriages because none of his clients wanted to give up custody of the house. Neutra invented California Modern Style. His houses are pavilions in the garden. Only transparent glass and thin posts act as raincoats against the elements. The houses look out, not in. The space flows easily between the garden and house, ceiling and sky.

Neutra (1892-1970) was the first of the International Style architects to practice in the United States. By 1929, he had already designed and built a modern house in California far in advance of the modern European architects.

For the past two decades or so, Neutra has been largely overlooked, his importance forgotten, his work left to decay. The post-modernist architects and their camp followers dismiss Neutra's work with Frank Lloyd Wright's criticism: "cheap and thin."

Now an exhibit and a book may well restore Neutra to his rightful place as a pioneer and the originator of the California Modern style. The exhibit, at the new wing of New York's Museum of Modern Art, continues through October.

MOMA's director of architecture and design, Arthur Drexler, put the show and its illuminating catalogue together with Thomas Hines, the author of the definitive and entertaining book, "Richard Neutra and the Search for Modern Architecture" (Oxford University Press).

The Museum of Modern Art exhibit teaches much needed lessons in providing elegant yet inexpensive housing for people today.

According to Drexler, the Neutra show came about almost by popular demand. The museum had commissioned a model of Neutra's masterpiece, the Lovell house, for its Best & Co. collection of architectural models. When it was shown, architects and public alike demanded more.

That model, its drawings and photographs show an innovative structure, the first steel-framed house in the United States. The house is also the sort of place we all expect a movie star to live in: cantilevered over a cliff, with verdant terraces and bands of stark white. It is a dramatic house; and it must have seemed shocking in 1929, even in Los Angeles.

The Lovells were the ideal clients for such a house. Philip Lovell, in his newspaper column, advocated a vegetarian diet and nude bathing.

The Lovell house--with model-T Ford headlights set in the stairway, three levels, roof decks, servants' rooms and heaven knows what else--cost $65,000, exclusive of the land, according to Neutra's records.

A house for the movie director Josef von Sternberg, built in 1935 and '36, is not such a cliff-hanger--actually it's on level ground. But it does have a moat (which Neutra used to say was wired to electrocute unwanted visitors) and a two-story hall. Ayn Rand, who wrote "The Fountainhead," a novel glorifying modern architecture, bought the house after von Sternberg. It has since been destroyed.

The vacation house on Fisher's Island, N.Y., for the John Nicholas Brown family (Carter Brown, director of the National Gallery, is a son), was another of Neutra's greatest houses. It had more than 30 rooms, including prefabricated baths by Buckminster Fuller. The house was not blessed with good fortune. According to Hines, once, during a hurricane, a window--frame and all--blew onto Carter Brown's bed just as he'd left the room. New Year's Eve, 1975, the house burned down.

Those are the epic works, the spectaculars.

But perhaps the most important and influential works shown are the small houses, some built in the '30s and '40s for as little as $3,000. Obviously they are quite small--almost detached efficiency apartments. But every inch is made to work--not only for convenience, but to lift the spirit.

Typically, the houses turn their backs to the street, opening up with sliding glass or large fixed panes of glass in the rear. The houses are also energy efficent.

The glass is sheltered with overhangs. The roofs are often used as terraces, sometimes even with pools.

Some of the houses are prefabricated, some built of unlikely materials such as sheet steel (painted silver to look like stainless). Others are plywood or stucco. The early houses are not always easy to maintain in the pristine condition their designs demand.

The houses are strongly influenced by Japanese vernacular architecture, in the same way that Japanese prints influenced art nouveau and the Sezession movement.

Though the bulk of his work was in California, in this area Neutra designed a handsome house in Northwest Washington, one in Richmond, and the Gettysburg Visitors' Center.

Neutra learned much from the Viennese architects of the period, especially Otto Wagner and Adolph Loos. It is no coincidence that the Museum of Modern Art is planning a blockbuster rediscovery exhibit of early modern Viennese architecture and decoration from the turn of the century through the world wars. The importance of the Viennese contribution to the modern style is just now being properly appreciated and the rediscovery of Neutra may well be part of it.

Hines' book and the exhibit also do a fine job of giving a picture of this remarkable man.

Both owe a great deal to the diaries, files and memories of Dione Neutra, the architect's widow, who still lives in their 1932 Los Angeles house, remodeled by their son Dion after a fire.

A photograph and a self-portrait in the exhibit make Neutra look rather like a matinee idol playing an Austrian movie director. His early charcoal sketches and watercolors make it plain that he was a competent artist in the manner of Gustave Klimt and Egon Schiele, the Sezession artists of Vienna.

He was born and educated in Vienna, Austria. He spent his mature career and life in California. In his life and works he combined all the best and all the worst of Austria and California: the easy charm, the quick facility and the tendency to live life as though it were a presentation of the opera house.

By all reports he suffered from manic-depressive attacks. He was often impossible to live with or work for. Without the support of his long-suffering wife, it is doubtful whether he could have functioned at all.

In an interview in Washington some time ago, Dione Neutra recalled that he had predictable, cyclic fits of depression. "Once, he was to speak to a great crowd of people in Dusseldorf when the depression hit. But I had a pint of vodka with me and he drank the whole thing. It was a wonderful, witty speech."

He took her everywhere, as secretary and booster. Only after his death was Dione Neutra, now in her eighties, able to pursue her interest in singing and playing the cello. "I often asked him for just three hours of practice time on Sundays," she said, "but he would always interrupt."

Hines writes of the long lists of questions Neutra asked his clients and cites the equally long and involved answers from John Nicholas Brown. Dione Neutra remembers that Brown's wife requested two tubs in the master bath. Dione Neutra also remembers that Neutra, unaware of the Brown fortune, had the family checked out by Dun & Bradstreet before he accepted the commission.

For his birthday once, she wrote all his clients and asked what the houses meant to their lives. The answers made joyful reading. "He once said, 'If I cannot fall in love with my clients, I can't serve them,' " she remembers.

But the best of his work gave people a place to live that was simple, elegant, inexpensive and, as Arthur Drexler put it, had no place to be sad.