There is little in the public domain about this élite international high-IQ society, MENSA, which boasts a membership tested to have an IQ among the highest two per cent of the population. This book was written by an insider who, as a member of MENSA, contributed extensively to this high-IQ society over a span of almost thirty years. MENSA was originally conceived of as a third pillar intended to complement the Royal Society and the British Academy. When it was founded in Oxford during 1946 its original goal was to gather six hundred of the most intelligent people in Britain, as scientifically measured through an IQ test, who the government and its agencies could contact for advice on matters of government. It had two purposes: first, to conduct research in psychology and social science and, secondly, to provide contact between intelligent people everywhere in the world. The intention was for MENSA to conduct three strands of research: To test intelligence tests, and identify correlations with intelligence. Mensans as the subjects of research. The Mensan as an instrument of research, i.e. where they themselves chose areas of interest to research and write reports on them. This book reveals some of the research conducted on or by Mensans over the intervening seventy years. Under its first president, Sir Cyril Burt, MENSA systematically conducted research on thousands of its members from 1946 until the death of the esteemed British psychologist in 1971. Burt's research was challenged after his death, but it is debatable whether his detractors were fully aware of his MENSA research. MENSA was conducting big data research long before it became fashionable during the 21st century with the advent of powerful computers, and much of this research was made available to government departments at the time.