Scientific racism was of crucial importance to the ideology of Nazism. Anti-Semitism was only one of the many forces that lead to the Holocaust. ‘The case against scientific racism’ examines various theories on scientific racism and its failings. A major problem with racial science is that it lacked a good understanding of the implications of the distinction between genetic variation in human populations, phenotypical differences such as external appearance, and cultural and behavioural characteristics. A confused biological determinism established itself, conflating genes, physiognomy, and culture. It is now known that ideas of ‘race’ and ‘racial’ hierarchy have no serious scientific basis.