The most comprehensive and detailed theatrical treatise of the ancient world, detailing analyses of dramatic texts, the theatre building, acting, staging, music, and even theatre-company organization, is

the Sanskrit Natyasastra, or "treatise on theatre" (begun in the second century a. d.).

Explanation:

Attributed to sage Bharata Muni, the Nāṭya Śāstra (Sanskrit Nāṭyaśāstra) is a Sanskrit text on the performing arts dating back 200BCE. It contains many chapters (36 chapters with a cumulative total of 6000 poetic verses) which show detailed treatments of all the diverse arts (drama, including dance, music, poetics, and general aesthetics) that are embodied in the classical Indian concept of the drama. Its main importance is subject to the fact that it justifies Indian drama as a vehicle of religious enlightenment.