9x9, 450 black & white, photos and 50 color photos The X-Planes conjure up images of Chuck Yeager first breaking the sound barrier in the X-1 or of the black, bullet-shaped X-15 streaking through the skies at over Mach 6. But there have been 48 more X-designations assigned, as well as a host of other experimental aircraft that did not fall into the formal X-series. Some of these investigated very low-speed flight, vertical take-off, or were technology demonstrators for production military aircraft. Others were missiles, or gliders. One was supposed to be a spacecraft.Tony R. Landis and Dennis R. Jenkins have assembled an outstanding collection of photographs documenting the X-Planes. These photographs come from government and company archives as well as personal and public collections. Hundreds of photos - some in color and many never-before-seen - detail the modern history of experimental flight.