The radical Douglas X-3 Stiletto was built primarily of titanium, and was intended to test high speed flight and low-aspect ratio wing design. Initial requirements indicated the aircraft would carry the J-46 engine and be capable of reaching cruising speeds above Mach 2.0. Problems with the J-46 engine, led Douglas engineers to substitute underpowered J-34 turbojets. Although the plane once achieved Mach 1.2 in a dive, it never went supersonic in level flight. Nevertheless, the plane was a valuable research tool and produced critical data about inertial coupling. The X-3 first flew in 1952 and was retired in 1956. Originally printed by the U.S. Air Force and NACA (later NASA), this hand- book provides a fascinating glimpse inside the cockpit of one of history's great planes. Classified "Restricted", the manual was declassified and is here reprinted in book form. Although slightly reformatted, care has been taken to preserve the integrity of the text.