This 1930 publication from the now defunct Pitcairn-Cierva Autogiro Company of America claims to be "the first complete authoritative presentation of the Autogiro; what it is, what it does, and how it does it." Juan de la Cierva, an airplane designer for the Spanish Air Force, invented the Autogiro in the early 1920s. In 1929, Harold Pitcairn acquired U.S. rights to Cierva's invention and formed the Pitcairn-Cierva Autogiro Company of America.
