Nature versus nurture sum up in a nutshell one of the most difficult debates in science. People’s qualities are determined by their genes (nature) or by their environment (nurture). The debate has only grown louder since the human has been found to have only 30,000 genes. Some scientists claim that we don’t have enough genes to account for all the existing human variations. Genes are designed to take their cue from nurture. Genes are not unchanging little bits of DNA. Their expression changes throughout a person’s life, often in response to the environment of that person. Babies are born with genes hard-wired for sight, but if they are also born with cataracts, the genes turn themselves off and the babies will never acquire the ability to see. Ridley’s survey of what is known about nature vs. nurture actions are conveyed with insight and style. Any readers looking for an interesting read will find this an engrossing study of what makes us who we are.