The announcement in 2003 that the Human Genome Project had completed its map of the entire human genome was heralded as a stunning scientific breakthrough: our first full picture of the basic building blocks of human life. Since then, boasts about the benefits?and warnings of the dangers?of genomics have remained front-page news, with everyone agreeing that genomics has the potential to radically alter life as we know it. For the nonscientist, the claims and counterclaims are dizzying?what does it really mean to understand the genome? Barry Barnes and John Dupré offer an answer to that question.