Sherwood L. Washburn, in Scientific American (Sept. 1978), 415 Madison Ave., New York, N.Y. 10017.
The study of human evolution has undergone radical change in the last 30 years, thanks to new fossil finds, improved understanding of radio- active isotope dating, and revelations in plate tectonics (e.g., that the great land masses of Africa and South America were once quite close). And the application of new specialties, such as molecular anthropology and field observation of primate behavior, offer...