Vaslav Nijinsky, "the god of dance," was surrounded by legend from the beginning of his dancing career. His virtuosity was extraordinary, his technique perfect; as a choreographer, he created a new concept of dance that astonished official culture and marked the beginning of modern ballet. On March 4, 1909, on the eve of his first psychiatric admission, Nijinsky interrupted the writing of these pages in which, with feverish, often incandescent language, he demonstrated a blinding lucidity and bequeathed to posterity the farewell of an artistic genius on the verge of definitive madness. In his Diary, Nijinsky reveals himself as a cultivated and radical artist with a deep understanding of Russian literature, politics, and thought, although the symptoms of his illness also persist, whether in the form of persecution mania or delusions of grandeur, hallucinations, or an obsession with sex. After his death, his wife, Romola Nijinsky, supervised and censored the Diary's editions: now we present, for the first time in Spanish and directly translated from Russian, its full version.