Anais Nin, a brilliant and innovative author who probed the inner landscapes of the mind in a series of sensitively written diaries she kept up over decades, died late Friday in a los Angeles hospital. She was 73.

Although her surrealist explorations of the subsconscious had often proved too obscure for the general public, she seemed to be gaining acceptance in recent years among the young, and among those who valued her vivid expressions of a woman's point of view.

The author of works of rare delicacy and fragile beauty, she was also a woman of great determination, who overcame the lack of a publisher in the 1940s by buying a foot-powered press and printing her own work.

In addition to the six volumes of "The Diary of Anais Nin," the last of which was published last year - by a commercial publisher - she was also known for a series of other works, including several novels.

The diaries offer keenly perceptive observations of her life in America and in Bohemian Paris, and of many well known literary and cultural figures whom she came to know, including Henry Miller, Antonin Artaud, Lawrence Durrell, and psychiatrist Otto Rank.

Miss Nin herself had been a practioner of psychology for a time. She had also been a fashion mannequin and artist's model, as well as a Spanish dancer, and had given dramatic readings.

Although she was years in gaining recognition. Miss Nin, whose perceptions have been compared to those of Proust, seemed destined from childhood to write.

Born in Paris in 1903, she was the daughter of Spanish pianist-composer Joaquin Nin and a French-Danish singer and society woman, Rosa Culmell.

"I was a writer from the age of 9," Miss Nin once said. "I signed my stories 'a member of the French Academy,' can you imagine!"

When she was 11, her father deserted the family. Her mother took Miss Nin and her brothers to New York, where Miss Nin entered the public schools, and, as a means of helping make endurable the abrupt dislocation in her life, began keeping a diary.

After leaving school at 15 to work and study on her own, she was married in 1920 to Ian Hugo, and then went back to France, where she lived in Louveciennes near Paris, until World War II.

In 1930, while in France, she published her first work, a long essay, "D. H. Larence: An Unprofessional Study." In 1931, she wrote "The House of Incest," and in 1935, "Winter of Artifice," a novelette.

She also worked steadily on the diaries - lyrical, confessional, realistic, surreal.

"At first I wrote about everything that happened," she said, "but as I matured, I became more selective and there are a great many portraits of people."

Searching in her examinations of others, she was not sparing of herself. Strapped for funds, at one point she found herself writing 80 pages a week of pornography for an anonymous "collector". She hated it.

"Anger, jealousy, envy, revengefulness, vanity," she said. "I locked them up in a diary."

Although impoverished and unrecognized, she constantly felt impelled to provide both financial and emotional support to many friends in the art and cultural worlds.

Eventually there was a breakdown, and in time, a recovery, with new awareness of what she viewed as the essential conflict of modern woman: the need to offer maternal nurturing versus the need for self-fulfillment.

"I write like a medium," she said in one of her diaries. "I fear criticism because I fear it will destroy my spontaneity. I fear restriction. I live by impulse and improvisation and want to write the same way."

When the "Winter of Artifice," though praised by critics, did not attract publishers in New York in the early 1940s. Miss Nin was undaunted.

She obtained a $100 advance from a bookstore, and raised another $100 from friends. She paid $75 for a second-hand press and $100 for type, and began to study printing. She also arranged credit with a bindery.

In about three months she had turned out 500 copies of "Winter of Artifice," and sold 400 through a vigorous telephone, mail and door-to-door campaign.

"A real writer does not need the publicity that is granted with equal fervor to a toothpaste," she said. "A real writer only wants his book to be read by those people who want to read it, and if there are 100 of them, it is enough to keep his work alive and sustain his productivity."

Praised by many literary figures, including Miller, Edmund Wilson, and William Carlos Williams, Miss Nin began in time to find a wider readership for her novels with their mystical, hallucinatory depiction of a world often trembling between dream and reality. Her works include 'Ladders of Fire," "Children of the Albatross," "The Four-Chambered Heart," "A Spy in the House of Love" and "The Seduction of the Minotaur."

In the 1960s, a major new York firm began publishing the diaries, which among other themes, focused attention on her struggle as a woman for freedom and recognition.

A delicate, sofe-spoken, nurturing, carefully groomed woman who had preservered quietly for years, she found herself much in demand among students and feminists. "Sometimes I feel like I have about 10 million daughters," she said in 1971.

In recent years, with notebook in hand, Miss Nin had been known to spend much of each day writing and editing the still unpublished volumes of her diary.

To a great degree her life remained a mystery.

"I will be very frank," she once said. "I need a certain anonymity in my personal life - not only because I need the privacy when I am working - but because there is a kind of plot to my diary.

"Whatever I tell about the present is like giving away the end of the story."