IN APRIL 1908, Agnes Ernst, a young reporter for the

New York 2 Sun, went to the Little Galleries of the Photo-Secession at 291 Fifth Avenue in New York to see the premier and enormously controversial exhibition of abstract drawings by the "wild man" Henri Matisse and to interview the gallery's impetuous impresario, Alfred Stieglitz. She asked Stieglitz what he was seeking to accomplish by showing such stuff. "If you do not know," he replied, "I cannot tell you because you would not understand." That answer, Stieglitz calculated, would either infuriate the narrow-minded or challenge those willing to consider new directions in art. While admirers concluded that Stieglitz was indeed a visionary, a persona he cultivated, his critics dismissed him as a windbag and a charlatan.

Ernst, for her part, was impressed. She believed, as she wrote, that Stieglitz's goals were "truth," "freedom," and "justice." Later, she even joined his cadre of artists and critics at 291, as the experimental gallery was called, and, after her marriage to the financier Eugene Meyer, became one of America's first patrons of modern art as well as a contributing editor of 291, an avant-garde sheet which appeared monthly in 1915-16.

In part because Stieglitz adamantly refused or was unable to put his ideas into print; in part because, following his death in 1946, his great collection of 20th- century art was divided among three museums; and, in part because most of his private correspondence remains closed, Stieglitz, if known to the general public at all, is known primarily as a photographer. This is a pity because, more than anyone else, he helped establish modern art in America, of which, for him, photography was only a part, albeit an integral one.

Fortunately, two new books, Stieglitz: A Memoir/Biography by Sue Davidson Lowe, a grandniece of Stieglitz, and Alfred Stieglitz: Photographs and Writings by Sarah Greenough and Juan Hamilton, have just been published. The first, as its title suggests, is a study of Stieglitz's life while the second is a catalogue for the magnificent retrospective of Stieglitz's photography which will be on view at the National Gallery from February 3 to May 8. These two very different books fill important gaps in what has been so far a sketchy outline of Stieglitz's life and accomplishments.

Stieglitz, the oldest son of German-Jewish refugees, was born in 1864 in Hoboken, New Jersey. He grew up in a large brownstone house on New York's East Side, where his father prospered as a wool merchant. In 1881 the elder Stieglitz felt he had made enough money to retire and take his family to Germany, whose schools, he believed, were more rigorous and whose culture, he was certain, was more refined.

For Stieglitz, the next nine years were formative ones, and provided the foundation for his future forays into the world of art. In Germany, he developed a keen and life-long appreciation for the intellectuals' desire to break through the limits of the material world in order to unleash the spirit, or the Geist, as they called it. And, more important for his immediate future, he discovered photography in 1883. (The current retrospective comes 100 years after he took his first pictures.)

For the next 25 years Stieglitz strove to establish photography as a legitimate form of art, which, he argued, could be a means of self-expression as valid as painting or poetry. As Sarah Greenough explains in her lucid and intelligent introductory essay to Alfred Stieglitz, he did so by stressing photography's distinctive qualities. Although he briefly experimented with manipulating either the negative or the print to create an "artistic" effect, Stieglitz soon became "straight" photography's foremost advocate. As such, he gained recognition as the unrivaled pioneer of modern photography. His early photographs, like "Spring Showers" (1901) and "The Hand of Man" (1902), are as fresh and vital today as when they were taken.

But Stieglitz soon grew bored by "the fight for photography," as he called his effort to win acceptance for the medium. Because to him photography represented a means to an end larger than itself, he decided in 1907 to expand his "fight" by showing other media as well as photographs at 291, the art gallery which he and his colleague, Edward Steichen, had founded two years before. During the next five years--five years before the Armory Show which introduced modern art on a grand scale to an uncomprehending American public--Stieglitz showed and sought to explain the Post-Impressionist art of Rodin, Matisse, Cezanne, and Picasso. His was the only gallery in New York before 1913 willing to display these new painters' creations, which so shocked the public and the critics.

Just as Stieglitz earlier was not satisfied taking pictures and promoting photography exclusively, he soon wanted also to do more than be the European avant- garde's agent in New York. He therefore turned his attention increasingly after the Armory Show to aiding American artists by selling their work to wealthy collectors like the Meyers or Duncan Phillips and by creating conditions in which "his" artists could work and grow. For psychological reasons described in Lowe's book, Stieglitz, at the age of 50, finally found his most comfortable calling--as a patron, protector, and provider for a small group of American artists including John Marin, Marsden Hartley, Arthur Dove, Paul Strand, and his future wife Georgia O'Keeffe (they married in 1924 after living together for six years). Together these artists transformed the face of modern American art before 1917, the year 291 closed and Camera Work, Stieglitz's spectacular quarterly, ceased publication.

Sue Davidson Lowe's Stieglitz provides the best account yet of this creative man's life. By relying on a new cache of early family letters, her intimate knowledge of Stieglitz and his family, and her marvelous ability to recreate the turbulent emotional and physical worlds in which Stieglitz lived, Lowe has written a book which finally captures the personality of Alfred Stieglitz. The Stieglitz who emerges from her pages is neither the sanctimonious "seer" of Dorothy Norman's earlier biography, nor is he the simple collector of art and artists as he appears in the art historians' pedestrian catalogues. He is iconoclastic, troubled, and self-deceived, but charismatic and lovable nonetheless. What he mainly wanted, it is clear after reading Lowe's well-researched book, was to define new ways of seeing and living.

From Lowe, we learn that the deepest root of Stieglitz's desire to change the world lay in his family, particularly in his competitive relationship with his tyrannical father, whose example in many ways Stieglitz sought to emulate and exceed. Stieglitz's father was an unusual businessman who detested the workaday world, preferring instead to live a life of culture. Like his son, he was an artist (a Sunday painter), and also like his son, he generously helped support friends who were artists. But the elder Stieglitz, at least in his son's eyes, was also a hypocrite; while professing to be devoted to non- material values, he treasured his money and frequently scolded his wife for spending it too freely. Later, Stieglitz would reject his father's seeming hypocrisy by claiming not to take an interest in pecuniary values. He hoped that the new, non-materialistic, and revolutionary world of art he helped introduce would replace the world of his father.

Nothing angered Stieglitz more than being called a "dealer." Since 1895, when he gave up the small printing press which his father had helped set up for him, Stieglitz had eschewed bourgeois values. He never worked for a living. Instead, he lived modestly off small but regular donations from relatives. He would not dream of selling his own work, doing commercial photography, or even retaining a commission from "his" artists' occasional sales. In Stieglitz's view, to have done so would have violated the high moral purpose which defined true art.

Lowe is most interesting when she describes Stieglitz's domestic situations: her discussions of his family background, the "noble whore" he slept with in Germany, his embattled marriages, first to a silly, conventional woman who neither understood him nor liked him very much, and then to Georgia O'Keeffe, who, very much like him, insisted on doing things her own way and in her own place. His affair with the young and beautiful Dorothy Norman is also described, as well as the other extramarital affairs which seemingly preoccupied the loud and neurotic Stieglitz clan. At times the narrative resembles a soap opera, and, in the end, the book's lack of speculation on the broader significance of its subject limits the importance of what otherwise is a splendid rendition of Stieglitz's life.

Alfred Stieglitz: Photographs and Writings focuses exclusively on one of his achievements, his photography. Unlike Lowe's Stieglitz, this book had Georgia O'Keeffe's blessing, and it reflects her high standards. It is a magnificent volume. Under the direction of Eleanor Caponigro, the Meriden Gravure Company (which also did Georgia O'Keeffe: A Portrait by Alfred Stieglitz five years ago) has brilliantly reproduced 73 prints, many of which have never before been published or seen by the public. They trace his development as a photographer from his first sentimental prints of European peasants in the 1890s to his formal studies of New York City's cold urban landscapes during the Depression. Missing from this representative sample are Stieglitz's many portraits of Dorothy Norman, a fact which may illustrate Georgia O'Keeffe's silent supervision of the project.

The Greenough/Hamilton volume also includes excerpts from Stieglitz's prolific writings. These short, dramatic passages from his early essays and private letters suggest that Stieglitz was something more than "first and foremost" a photographer, which is how the designers of the book and the retrospective present him.

"I have all but killed myself for Photography," the authors quote Stieglitz exclaiming in 1923. "My passion for it is greater than ever. It's forty years that I have fought its fight--and I'll fight to the finish--singlehanded & without money if need be. It is not photographs--it is not photographers--I am fighting for. And my own photographs I never sign. I am not fighting to make a 'name' for myself. Maybe you have some feeling for what the fight is for. It's a world's fight. This sounds mad . . . All that's born of spirit seems mad in these (days) of materialism run riot."

Alfred Stieglitz's "fight for photography" was bigger than the pictures he took, the paintings he showed, or the art he collected. It was an all-encompassing vision of a world which we have not yet glimpsed, and perhaps never will.