TO call Robert Hass the eighth poet laureate of the United States is somewhat misleading. The office has existed in one form or another since 1937. Prior to 1986, when Robert Penn Warren returned to the office after 40 years and first accepted its current title, his predecessors were known more blandly as ''consultants in poetry.''
The poet laureate is a spokesperson for his or her craft, a custodian of poetry in American culture. The job is fairly and deliberately unstructured. The office, which is privately funded, requires the holder to act as a consultant to the Library of Congress, advising the institution in regard to the forces and trends in American literature.
Each year, the laureate helps select new poets to read in the Library's series and to be added to the archives of artists reading their own work.
Beyond that, the officeholder is free to pursue special projects - limited, of course, by the funds he or she can raise.
Rita Dove, the outgoing laureate, conducted a special symposium entitled ''The Black Diaspora'' and a reading by Crow Indian poets. Allen Tate, consultant from 1943 to 1944, edited an anthology of American poets of the early 20th century. Joseph Brodsky, laureate from 1991 to 1992, tried to spread poetry in supermarkets, hotels, and airports. His funds - and tenure - expired before he caught up with the Gideons.
Among those appointed to the office have been Robert Lowell (1947 to 1948); William Carlos Williams (who was named in 1952, but did not serve); Robert Frost (1958 to 1959); Howard Nemerov (1963 to 1964); Stanley Kunitz (1974 to 1976); and Maxine Kumin (1981 to 1982).
Term of office lasts one year. That few have served a second term may have something to do with the intense demands of the position. From the day he was chosen last May, Professor Hass has received floods of mail, manuscripts, requests for interviews, and invitations to speak. Lately, his answering machine has been logging more than 30 calls a day.
''All my predecessors warned me that you'll be immediately deluged with millions of letters and requests to do all sorts of things,'' he says. ''And that's been the case.''