By 1950, an estimated 50,000 people had been deemed ‘defective’ by the government and detained for life under the 1913 Mental Deficiency Act. Their ‘crimes’ were various: women with children born outside of wedlock; rebellious teenagers caught shoplifting; those with learning disorders, speech impediments and chronic illnesses who had struggled in school; and, of course, those who were simply ‘different’. Forcibly removed from their families and confined to a shadow world of specialist facilities in the countryside, they were hidden away and forgotten about, out of sight, out of mind. Through painstaking archival research, Sarah Wise pieces together the lives irrevocably changed by this devastating legislation and provides a compelling study of how early 20th-century attitudes to class, gender and disability have continued to shape social policy.