This is the Original preliminary art created for the cover of Poul Anderson's fantasy novel, published by Ballantine 1975 (I show the published cover for reference)  This early title by DKS was one of his most dynamic compositions...the final art was also seen in his collector card set, #27, titled "Clash of Wills".   Handpainted in acrylic on illustration board, 7" x 4.25".