The book analyzes the mystery foundations of R. Wagner's work. The opus, which concludes the composer's creative path, was an opera-mystery. All the previous musical and stage works, beginning with The Flying Dutchman, were approaches to the creation of a summarizing opus. The mystery foundations of R. Wagner's work are conceptualized by the author of the monograph through the prism of the great composer's transversal world outlook. In R. Wagner's work, the idea of Kunstreligion reflects the composer's religious and philosophical picture of the world, which was the result of his heuristic quest. R. Wagner's interaction with cultural and historical heritage reflects his interest in the knowledge that was accumulated in various areas of social consciousness. The book is addressed to musicologists, culturologists, as well as to a wide range of readers with a heuristic interest in these areas of humanitarian knowledge.