The book tells about the origin and true meaning of the theater and its connection with the ancient Mysteries, which conveyed the secret knowledge about man and the Universe. The focus of the author's attention is directed to the great Aeschylus, who is considered the creator of the tragedy genre, and to those few of his works that have come down to us.Х. A. Livraga writes: “We teach our children that theater, compared to reality, is just a fiction, a copy that more or less distorts the essence of the original. It's a lie! Theater is the highest Reality, not constrained by the framework of space and time. He is a human creation in form only. But the very spirit of the Theater is deeply metaphysical, and that is why we call it the Mystery Theatre, because it has its roots in the most ancient Mysteries and was their more accessible form. To be more precise, the Greek theater, which flourished in the 5th century BC, originated from the Mysteries of Eleusis, a city that was culturally and geographically close to Athens.