Reviews several books concerning zoology. `Unto Others: The Evolution and Psychology of Unselfish Behavior,' by E. Sober and D.S. Wilson;`Machiavellian Intelligence II: Extensions and Evaluations,' by A. Whiten and R. W. Byrne; `Biopsychologie, eine Einfuhrung,' by J.P.J. Pinel; `Neorobiology,' edited by D. Robinson.