Two legends, one foundation: The Porsche 934 and 935 were all based on the 1974 Porsche 930 Turbo. Depending on the racing regulations, different race cars were developed from this: the 934 for Group 4 (the so-called "improved Gran Turismo") and the Porsche 935 for endurance racing in the manufacturer's world championship according to FIA Group 5. With these turbo twins, Porsche dominated the motorsport scene almost at will. The powerful machines, with between 380 and 845 horsepower, helped Porsche secure numerous world championship titles. This volume tells their story: with all technical data, race results, and meticulously researched vehicle biographies.