Packed with never-before-seen photos, plans and meticulous new digital artwork, this is the first history of the USAAF's futuristic World War II prototype interceptor, the XP-67 "Moonbat". The series of X-planes that sprang from the US Army's Request for Data R40C, focused on high-altitude, high-speed, long-range bomber interceptors. Among these aircraft was the McDonnell Aircraft Company's first ever clean sheet design, the XP67. Its futuristic lines promised performance that it was ultimately unable to deliver, but development was still underway when disaster struck. Just before Army performance demonstration flights were scheduled to begin, an engine fire destroyed the only XP-67 prototype, leaving a host of unanswered questions about what might have been, and leading to decades of continuing fascination with the XP-67 among aviation buffs and aircraft modelers. The authors of this book have uncovered new sources of information and a wealth of photographs and line drawings that document not just the XP-67 but also its immediate precursors within the McDonnell Aircraft design community, as well as alternative configurations for unbuilt variants aimed at different missions. Packed with unpublished photos of all stages of construction including key airframe changes made after initial flight tests, showing in detail how the final configuration was evolved, this volume finally provides clear focus on a story that has long been shrouded in mystery.