A history of World War II detailing racial antagonisms that motivated Americans and Japanese was among the winners of the 1986 National Book Critics Circle Awards. John W. Dower's ``War without Mercy: Race and Power in the Pacific War,'' won the award for general nonfiction in the voting this week by the 24 members of the organization's board of directors. ``Kate Vaiden,'' by Reynolds Price, won the prize for fiction. The award for biography went to ``Tombee: Portrait of a Cotton Planter,'' by Theodore Rosengarten. ``Wild Gratitude,'' by Edward Hirsch, won the poetry award; ``Less than One: Selected Essays,'' by Joseph Brosky, won for criticism. The awards will be presented in a ceremony at New York University on Jan. 29.