Why do we behave the way we do? Biologist Paul Ehrlich suggests that although people share a common genetic code, these genes "do not shout commands at us . . . at the very most, they whisper suggestions." He argues that human nature is not so much the result of genetic coding; rather, it is heavily influenced by cultural conditioning and environmental factors. With personal anecdotes, a well-written narrative, and clear examples, Human Natures is a major work of synthesis and scholarship as well as a valuable primer on genetics and evolution that makes complex scientific concepts accessible to lay readers.

"I doubt whether anyone will write as good a book of this sort on [human evolution] for another two or three decades." ( Science )

"Ehrlich's book is so well researched and so elegantly presented that it stands as one of the best introductions to human evolution in recent memory." ( Publishers Weekly , starred review)

埃力剋（1932— ），美國生物學傢、生態學傢、人口統計學傢、教育傢。1957年獲堪薩斯大學博士學位，現為斯坦福大學生物科學係人口學教授、保護生物學中心主任。1968年因《人口炸彈》一書、提齣人口增長與有限資源的告誡而成名。他是美國科學院院士、美國藝術與科學院院士，2012年當選倫敦皇傢學會會員。獲約翰·繆爾奬、剋拉夫奬（生態學的“諾貝爾奬”）、世界生態學奬、藍色星球奬、傑齣生態學傢奬等眾多奬項。有《蝴蝶與星球》、《生物學與社會》、《種族炸彈》、《地球》、《新世界，新思維》、《對科學和理性的背叛》及《鋼索上的人類》等三十餘部著作。盡管他的預言飽受爭議，他仍然堅信人口過多對人類生存和地球環境構成直接威脅。