well first off the book blows you off with the way the facts and figures have been systematically arranged and the book takes you on one part of human history to another . the book reminds us that even though with all the technologies and science we have invented and discovered we are not so different from the hunter gatherers many years ago . overall the book gives a you a whole new way in which we look ourselves and our society and does give us or at least me an existential crisis at the end of the book . a must read for those who are interested in a brief story of human biology and history