Proust's letters: a sort of autobiography; Selected Letters (1880-1903), by Marcel Proust. Edited by Philip Kolb. Translated by Ralph Manheim. New York: Doubleday & Co. 362 pp. $19.95.

This is a selection from the first three volumes of the nine-volume edition of Proust's letters currently being published in France under the editorship of the American Proust scholar Philip Kolb. It has been said that his correspondence comprises ''the autobiography that Proust never wrote'' - and indeed this picture of his early years vividly shows the fledgling writer tentatively moving out of the nest of family security, addressing himself to (male) lovers and possible patrons among the aristocracy of his day, and in general living the raw material of what would later become ''Remembrance of Things Past.'' Many readers may be unable to stomach Marcel's fawning notes to his ''enchanting little Mama'' and his shameless flattery of the beau monde. But the letters also display - in his longing for some transcendent great love and in his determination to rise above his rather silly personal feelings - persuasive evidence of the intellect and genuine artistic boldness that made him a great novelist.