Superior: The Return of Race Science is an investigative work by science journalist Angela Saini examining the history and modern revival of the idea that humanity can be divided into biologically distinct racial groups with meaningful differences in intelligence, behavior, ability or worth.

Saini investigates how ideas about race became intertwined with science, anthropology, biology, genetics and social policy, particularly during the nineteenth and twentieth centuries. She traces how early scientists attempted to classify human populations into racial hierarchies and how these ideas were later used to justify colonialism, slavery, segregation, eugenics and other forms of discrimination.

The book then moves into contemporary science, asking an important question: Has race science really disappeared, or has it simply changed its language?

Saini examines modern research involving genetics, intelligence, ancestry and human variation, looking at how scientific findings can be interpreted—or misinterpreted—to support preconceived ideas about racial differences.

A major theme is the distinction between human genetic variation and socially constructed racial categories. Human populations do show genetic differences associated with ancestry and geography, but Saini explores why translating those differences into rigid biological “races” can be scientifically misleading and socially dangerous.