Wagner's ideas on art and the function of his works in a broader cultural context. The opening of the text presents an "Avant-Propos" where the translator discusses the necessity of a faithful prose translation of Wagner's operatic cycle for a contemporary French audience. The translator emphasizes the importance of studying Wagner's ideas and principles before approaching the operas, urging readers to comprehend the underpinning aesthetic values that guide the works. Through this, the translator advocates for a deeper appreciation of Wagner's artistry, arguing against superficial interpretations and stressing the transformative power of Wagner's theatrical vision, which he defines as essential for experiencing the intended meaning of the operas. (This is an automatically generated summary.)