Richard Ferdinand Kahn was born in 1905, in Hampstead, England. He studied at St. Paul School and at Kings College of Cambridge. At age 25, Kahn formulated the idea that would be duly pinched by his master, John Maynard Keynes, and made the centerpiece of the latters General Theory. (Richard F. Kahn) This vital fundamental idea would help Keynes be labeled as the greatest economist of the 20th century. (Skidelsky)