Could our sense of who we are really turn on a sliver of DNA? In our multiethnic world, questions of individual identity are becoming increasingly unclear. Now bestselling author Jon Entine vividly brings to life the profound human implications of the Age of Genetics while illuminating one of today's most controversial topics: the connection between genetics and who we are, and specifically the question Who is a Jew? Entine weaves a fascinating narrative, using breakthroughs in genetic genealogy to reconstruct the Jewish biblical tradition of the chosen people and the hereditary Israelite priestly caste of Cohanim. Synagogues in the mountains of India and China and Catholic churches with a Jewish identity in New Mexico and Colorado provide different patterns of connection within the tangled history of the Jewish diaspora. As people from across the world discover their Israelite roots, their riveting stories unveil exciting new approaches to defining one's identity. Not least, Entine addresses possible connections between DNA and Jewish intelligence and the controversial notion that Jews are a race apart.