The theatre of Diokaisareia (Cilicia, Asia Minor) has been partially excavated in 1993 by a team of Turkish archaeologists, when a large part of the cavea and part of the scaena have been brought to light. On this occasion many elements of the architectural decoration were uncovered and a significant fragment of the dedicatory inscription was rediscovered. This text allows to date the building during the principate of Marcus Aurelius and Lucius Verus, making this theatre the only dated monument so far in Roman Cilicia. Now the remains have been studied within the German research project directed by Detlev Wannagat. The purpose of the volume is to make a complete survey of the main architectural features of the theatre. Starting from the collation of travellers'notes and photographs, in breadth and detail Marcello Spanu analyses and illustrates all available data. The study provides a detailed survey of the ancient structures and a thorough catalogue of all the preserved architectural elements, accompanied by an accurate graphic and photographic documentation. Starting from these data, the author proposes the reconstruction of the monument, taking into account its main features and its situation within the ancient city's topographic layout. The book offers new light on the researches on Cilicia and on Asia Minor, proposing new hypothesis on architecture of ancient theatres and on architectural decoration history.