D.S. Allan, a Cambridge M.A., is a science historian specializing in paleogeography, particularly in the Arctic regions. A science teacher for many years, he is a skilled cartographer and has made a special study of evidence for climatic and landform change in recent geological times. He lives in Basildon, Essex, England. J.B. Delair, B.Sc., is an Oxford-based geologist with wide international and commercial field experience. An anthropologist, he has a special interest in animal and plant distribution and in tribal traditions. He is the Museum Curator of Geology at University of Southampton, England.