Inside the Black Box of ‘White Backlash’ researches the contents of the letters of support sent to British politician Enoch Powell in the wake of his so-called ‘Rivers of Blood’ speech of April 20, 1968. Never has a politician received so much written support in so short a time. This book takes a thematic approach to investigate the way British whites used Powell’s speech to vent their frustrations, anger, hostility against (non-white) immigrants and the evolution of British society in the late 1960s. Each chapter unpacks one facet of a 10,000-letter sample, out of the approximately 100,000 letters Powell received: Race, State, War, Empire, America, Class, Gender, Elites, Parties, ‘Against’ - with this last chapter analysing letters of protest against Powell. This extraordinary archival material provides an altogether unique window into British society in the late 1960s and reads like a (white) anthropology of nativist Britons in times of swift change. The book will be of interest to both students and academics of race, immigration and ethnicity, as well as by the general public.