Kampourakis argues that DNA ancestry testing cannot reveal a person's true ethnic identity because ethnic groups are socially and culturally constructed. In 10 accessible chapters, he explains the assumptions underlying the scientific study of ancestry, and the resulting paradoxes that are often overlooked. What the study of human DNA mostly shows is that human DNA variation is continuous, and it is not possible to clearly delimit ethnic groups based on DNA data. As a result, we all are members of a huge, extended family, and not of genetically distinct ethnic groups. What ancestry tests can provide are probabilistic estimations of similarities between the test-takers and particular reference populations. This does not devalue the results of these tests, however, because they can indeed provide some valuable information to people who may not know much about their ancestors. In fact, what the tests are very good at doing is finding close relatives, and this is perhaps why the whole enterprise should be rebranded as family, not ancestry, testing. Ultimately, this book reveals that genetic essentialism, biological ethnic identities, racial superiority, and similar social constructs are scientifically unsupported.