Non-fiction book, first published: St. Martin's, 1971
Chapters treating early man as already human rather than vicious or animalistic begin with "The Old Man Hopes for Meat", continue with "The Dispossessed", "Human Body", "Predator", "Apology to Neanderthal" and end with "Man Comes in Age".
Becker, Muriel R.: Clifford D. Simak: A Primary and Secondary Bibliography, p.45