Been in the Storm So Long, by Leon F. Litwack. New York: Vintage Books. $7 .95.

This book, which won the 1980 Pulitzer for history, marks a major departure in the study of America's transition from slavery to freedom. An eloquent and insightful account, it captures what Litwack describes as the "dimensions of human tragedy." Across the pages stride black and white human beings clothed in the strengths and frailties which wars tend to expose with brutal clarity. Here Litwack not only chronicles the death throes of slavery, an institution far older than the American Republic, but also describes the ambiguous birth of black freedom, a reality with which the republic has yet to deal fully.