Hailed by many as the greatest racing car of all time, the 917 story is packed with superlatives. It began with an incredible display of 25 complete cars to achieve homologation in 1969. The following year, the 917 gave Porsche its first-ever win at Le Mans and repeated the result in 1971. Meanwhile, the factory-backed JW Automotive 917s captured the World Championship of Makes for Porsche in both years. Gordon Wingrove worked for JW Automotive during the 917 years and saw first hand what made these cars so special. In a book that sparkles with personal experience, he combines significant contributions by the Porsche engineers who created the car and his own incisive understanding to produce a remarkable technical appraisal. Every aspect of the design and development of the 917 is considered, from its innovation and ruthless pursuit of performance, to the teamwork and inspirational leadership that produced such startling results. Endurance racing was never the same again after the 917 era and this book demonstrates why.