For better or worse, Wagner is the most widely influential figure in the history of music. Around 1900, the phenomenon known as Wagnerism saturated European and American culture, influencing a procession of writers, artists, and thinkers, including Charles Baudelaire, Virginia Woolf, Isadora Duncan and Vasily Kandinsky. Anarchists, occultists, feminists, and gay-rights pioneers saw him as a kindred spirit. Then Adolf Hitler incorporated Wagner into the soundtrack of Nazi Germany, and the composer came to be defined by his ferocious anti-Semitism. His name is now almost synonymous with artistic evil. Wagnerism restores the magnificent confusion of what it means to be a Wagnerian. A pandemonium of geniuses, madmen, charlatans, and prophets do battle over Wagner’s many-sided legacy.