Lincoln: the role of myth and fact in history; Abraham Lincoln: The Man Behind the Myths, by Stephen B. Oates. New York: Harper & Row. 224 pp. $12.95; Our Fiery Trial: Abraham Lincoln, John Brown and The Civil War Era, by Stephen B. Oates. Amherst, Mass.: University of Massachusetts Press. 150 pp. $7.95 paperback.

LITERARY historian and biographer Stephen B. Oates re-creates the life and world of Abraham Lincoln with the skill of a master painter, using images and colors on a canvas. ''Our folly as a nation,'' he writes, ''is that we too often confuse myth with history.'' In these two books, one a biographical study of Lincoln and the other a collection of interrelated essays, Mr. Oates succeeds in portraying both the facts and myths of history as essential to our understanding it.Viewing history as myth allows us to rediscover ''our spiritual needs as a country,'' and the philosophical intentions of Lincoln and his era indicate the purpose of myth in the development and policies of our country. His other contention is that the myths we believe alter our perceptions of history.

Oates accomplishes these goals by studying past biographies of Lincoln, from Hearndon's to Sandburg's to the forthcoming ''Lincoln'' by Gore Vidal. In ''Our Fiery Trial,'' he criticizes William Styron's ''Nat Turner'' for its lack of factual evidence, relying on his own research as the author of a ''Civil War Tetralogy'' (books on John Brown, Abraham Lincoln, Nat Turner, and Martin Luther King Jr.). Thus, he is able to reevaluate other historians in terms of their biases and faulty research, demonstrating how biographers sometimes serve their own ends rather than their material.

Oates cites Lincoln's poetry (which is, interestingly, not bad) to demonstrate Lincoln's contemporaneity to his own times, and through this method a more complex man emerges, one who dealt with the problems of offending his contemporaries and of weighing decisions which would establish historical precedents for black and white, North and South.

Oates writes with a precision that a lawyer would envy, but he is able to combine an enormous amount of research with an appealing literary style to demonstrate how those who love the romance of history may not adhere to its realities. In his ''Civil War Tetralogy,'' he presents American history as a dialogue between the lives of black and white men, illuminating an epoch which had previously been reduced to a series of cliches.

Unlike many contemporary historians and biographers, Oates realizes that history must be more than ''the sum of one's research notes,'' and so he re-creates telling scenes, such as Lincoln's assassination, with blacks and whites waiting outside while he died, and the somber and emotional closing of Mary Lincoln's life as she fingered her wedding ring, inscribed ''love is eternal,'' while lying on her side of the bed, as if Lincoln would soon enter the room to join her.