AROUND LINCOLN'S birthday every year, the school children of America are exposed to a concentrated dose of black American history. These reviews usually focus on the accomplishments of Americans of note who happen to have been black. It is in such a period that children will be reminded that "Deadwood Dick," the legendary cowboy, was black, that George Washington Carver discovered more than 3,000 uses for the peanut and that a black man, Dr. Charles Drew of Washington, found a reliable method of separating blood plasma, thus helping to save thousands of lives during World War II.

This year there is a difference, brought about in large part by Alex Haley's "Roots." The focus is now on slavery and its legacy, and the nation has been made aware of an aspect of history that is not usually dealt with on prime-time television. Furthermore, it is now black history month , an innovation thought up for last year's bicentennial by the Association for the Study of Afro-American Life and History. The association wanted Americans to focus on the subject for Longer than a week.

When you think about the idea of a week (or a month) devoted to black history, you have to wonder whether we are not rapidly approaching a time when such "set asides" will be irrelevant. In the past, when history texts simply omitted discussion of blacks, some device was need to remind the country that such people existed and made important contributions to the nation's life and history.

Now, black Americans themselves are making the country aware of their history, not just through Mr. Haley's "Roots" but also through books about other aspects of the black experience. The historian Nell Painter, for example, has just completed a widely acclaimed study of the experience of ex-slaves as they sought to migrate from the deep South to Kansas after the Civil War. It is alive with the experience of the frontier and with deep disappointments the "exodusters" from the South experienced. Studies of this sort will help to fill a void that has existed in scholarship and in the texts used to teach history to the nation's schoolchildren.

As time goes on and more is published, these special "black history" periods - whether a day, a week or a month - will become less necessary. And that is as it should be. For what is important to remember is that Afro-American history had no business being separated from American history in the first place. The contribution of black Americans is unique in many respects. But little by little, we are coming to recognize that ours is one history. Understanding that history is essential to understanding who we are. With any luck one of these days someone will forget to call black history week (or month) - and hardly anyone will notice.