Race is often defined by its reference to biology, "blood", genes, nature or essence. Yet these concepts are often left unexamined. Integrating material from the history of science, science studies, and anthropological studies of kinship and new reproductive technologies, as well as from studies of race, Peter Wade explores the meaning of such terms and interrogates the relationship between nature and culture in ideas about race.

Wade argues that, over previous centuries in the West, human nature has been conceptualized as a combination of pre-determined and flexible factors. In the twentieth century, despite the nature versus nurture debate, our understanding of what makes up human identity and character continues to blur the boundaries between the two. Exploring the complex interconnection between nature and culture in making persons what they are, Wade argues that these ideas of biology and nature that underwrite racial discourse are more complex than they seem. Using studies of public understandings of genetics and of ideas about the "natural" ties of kinship, he shows that everyday understandings of race still invoke "biology" and "blood", and that the common assumption of a general shift to "cultural racism" is premature.

Offering a clear and insightful explanation of the key issues, Wade argues that biology is not seen as a clearly fixed category. Looking at race from the unusual perspective of anthropology, he develops the idea of biology as a process, and contends that racial identity may become embodied. The sedimentation of the cultural effects of racial identity into the physical body underlies the apparent contradiction between race as fixed and race as flexible.