In addition to his photography, Stieglitz was known for the New York art galleries that he ran in the early part of the 20th century, where he introduced many avant-garde European artists to the U.S.

The following year, his family began spending the summers at Lake George in the Adirondack Mountains, a tradition that continued into Stieglitz's adulthood.

He enrolled in a chemistry class taught by Hermann Wilhelm Vogel, a scientist and researcher, who worked on the chemical processes for developing photographs.

The next year he won both first and second prizes in the same competition, and his reputation began to spread, as several German and British photographic magazines published his work.

In order to avoid the appearance of bias in his opinions and because Photochrome was now printing the photogravures for the magazine, Stieglitz refused to draw a salary.

He told journalist Theodore Dreiser he wanted to "make the club so large, its labors so distinguished and its authority so final that [it] may satisfactorily use its great prestige to compel recognition for the individual artists without and within its walls.

The strain of preparing for this show, coupled with the continuing efforts to produce Camera Notes, took a toll on Stieglitz's health.

In December 1901, he was invited by Charles DeKay of the National Arts Club to put together an exhibition in which Stieglitz would have "full power to follow his own inclinations.

"[14] Within two months Stieglitz had assembled a collection of prints from a close circle of his friends, which, in homage to the Munich photographers, he called the Photo-Secession.

[15] He began formulating a plan to publish a completely independent magazine of pictorial photography to carry forth the artistic standards of the Photo-Secessionist.

[8] In the October 1906 issue of Camera Work, his friend Joseph Keiley said: "Today in America the real battle for which the Photo-Secession was established has been accomplished – the serious recognition of photography as an additional medium of pictorial expression.

He decided to show her work because he thought it would be "highly instructive to compare drawings and photographs in order to judge photography's possibilities and limitations".

Although an announcement of an open competition for the show was printed in Camera Work, the fact that Stieglitz would be in charge of it generated a new round of attacks against him.

An editorial in American Photography magazine claimed that Stieglitz could no longer "perceive the value of photographic work of artistic merit which does not conform to a particular style which is so characteristic of all exhibitions under his auspices.

"[21] Stieglitz wrote to fellow photographer George Seeley "The reputation, not only of the Photo-Secession, but of photography is at stake, and I intend to muster all the forces available to win out for us.

By the summer of 1912, he was so enthralled with non-photographic art that he published an issue of Camera Work (August 1912) devoted solely to Matisse and Picasso.

He also agreed to be listed as an honorary vice-president of the exhibition along with Claude Monet, Odilon Redon, Mabel Dodge and Isabella Stewart Gardner.

He later wrote that allowing people to see both photographs and modern paintings at the same time "afforded the best opportunity to the student and public for a clearer understanding of the place and purpose of the two media.

What is less known is that he conditioned this statement by following it with these words: PLEASE NOTE: In the above STATEMENT the following, fast becoming "obsolete", terms do not appear: ART, SCIENCE, BEAUTY, RELIGION, every ISM, ABSTRACTION, FORM, PLASTICITY, OBJECTIVITY, SUBJECTIVITY, OLD MASTERS, MODERN ART, PSYCHOANALYSIS, AESTHETICS, PICTORIAL PHOTOGRAPHY, DEMOCRACY, CEZANNE, "291", PROHIBITION.

Energized by this activity, he began one of his most creative and unusual undertakings – photographing a series of cloud studies simply for their form and beauty.

[27] In 1924, Stieglitz's divorce was finally approved by a judge, and within four months he and O'Keeffe married in a small, private ceremony at Marin's house.

O'Keeffe said later that they married in order to help soothe the troubles of Stieglitz's daughter Kitty, who at that time was being treated in a sanatorium for depression and hallucinations.

[24] For the rest of their lives together, their relationship was, as biographer Benita Eisler characterized it, "a collusion ... a system of deals and trade-offs, tacitly agreed to and carried out, for the most part, without the exchange of a word.

"[27] In the coming years O'Keeffe would spend much of her time painting in New Mexico, while Stieglitz rarely left New York except for summers at his father's family estate in Lake George in the Adirondacks, his favorite vacation place.

The Strands raised nearly sixteen thousand dollars for a new gallery for Stieglitz, who reacted harshly, saying it was time for "young ones" to do some of the work he had been shouldering for so many years.

It was one of the few times he acted spitefully to O'Keeffe in public, and it might have been as a result of their increasingly intense arguments in private about his control over her art.

"[27] In 1936, Stieglitz returned briefly to his photographic roots by mounting one of the first exhibitions of photos by Ansel Adams in New York City.

Stieglitz was cremated, and, with his niece Elizabeth Davidson, O'Keeffe took his ashes to Lake George and "put him where he could hear the water.

In 1949, she donated the first part of what she called the "key set" of 1,317 Stieglitz photographs to the National Gallery of Art in Washington, DC.

In 2002 the National Gallery published a two-volume, 1,012-page catalog that reproduced the complete key set along with detailed annotations about each photograph.