Mariya-Cecilia Abramovna Mendelson-Prokofieva, typically referred to as Mira Mendelson, was a Russian poet, writer, and translator who was the second wife of the composer Sergei Prokofiev. She was the co-librettist of her husband's operas Betrothal in a Monastery, The Story of a Real Man, and War and Peace, as well as the ballet The Tale of the Stone Flower.

War and Peace is a 1946 230-minute opera in 13 scenes, plus an overture and an epigraph, by Sergei Prokofiev. Based on the 1869 novel War and Peace by Leo Tolstoy, its Russian libretto was prepared by the composer and Mira Mendelson. The first seven scenes are devoted to peace, the latter six, after the epigraph, to war.