The Wright brothers, Orville (1871-1948) and Wilbur (1867- 1912), were two Americans who are generally credited with inventing and building the world's first successful airplane and making the first controlled, powered and sustained heavier-than-air human flight in 1903. In the two years afterward, the brothers developed their flying machine into the first practical fixed-wing aircraft. Although not the first to build and fly experimental aircraft, the Wright brothers were the first to invent aircraft controls that made fixed wing flight possible. The brothers' fundamental breakthrough was their invention of "three axis-control", which enabled the pilot to steer the aircraft effectively and to maintain its equilibrium. They gained the mechanical skills essential for their success by working for years in their shop with printing presses, bicycles, motors, and other machinery. The brothers' contracts with the U. S. Army and a French syndicate depended on successful public flight demonstrations that met certain conditions. The brothers had to divide their efforts. Wilbur sailed for Europe; Orville would fly near Washington, D.C. They are the authors of The Early History of the Airplane (1922).