Early humans did not move north gradually from their tropical homeland as they adapted to the cold, reports Hoffecker (Arctic and Alpine research, U. of Colorado-Boulder), but in relatively rapid bursts of expansion. Spanning two million years, his study describes the movement out of Africa, the first Europeans, cold weather people, modern humans in the north, moving into the Arctic, and peoples of the circumpolar zone. Annotation ©2004 Book News, Inc., Portland, OR (booknews.com)