The book describes the evolution of the modern dragon from its ancient forebears, in terms both of its form and of its narrative contexts. In physical form dragons are broadly serpentine, but have animalian heads, thick central bodies, wings, and clawed legs. In their stories they live in caves, lie on treasure, maraud, and burn; they are extraordinarily powerful, but even so ultimately worsted in their battles with humans. Despite the inestimable success of this physical form and this broad story-type, there is nothing obvious, inevitable, or natural about them. Rather, both are mature, complex, and artificial constructs. The book traces the evolution of the dragon’s form from the purely serpentine drakon of classical antiquity, through its merging with the forms of the ancient sea monster and the winged, humanoid demon, into that of the first recognizably modern dragon, the two-legged wyvern that emerged in the illustrated manuscripts of the ninth century ad, which has previously been described as the ‘Romanesque’ or ‘Gothic’ dragon. It traces the evolution of the dragon’s typical story-type again from classical antiquity, across the vast tradition of medieval hagiography (saints’ lives), and into the Germanic world, where particular attention is given to the wealth of dragons featured in the Norse sagas.