Diego Rivera made the following sketches during a seven-to-eight-month stay in the Soviet Union between 1927 and 1928. A prominent member of the Partido Comunista de México (Communist Party of Mexico), Rivera traveled to Moscow to participate in the tenth-anniversary celebrations of the 1917 Revolution. Word of Rivera's dedication to muralism as a politically potent art form preceded his arrival, and he quickly became embroiled in debates about Soviet art's ideological aims and physical characteristics. He lectured on monumental painting at the Komakademiia (Communist Academy) and joined the Oktiabr' (October) group, a body of artists—many former Constructivists—working in varied media but united in their rejection of easel painting in favor of works intended for public display and mass audiences. Rivera also received a commission from Anatolli Lunacharsky, the first Soviet Commissar of Enlightenment, for a fresco cycle (ultimately unrealized) at the Red Army's headquarters. As Maria Gough argues in this issue, the group of drawings, long assumed to be from a single notebook, is likely an amalgamation of sketches created during two distinct events, the tenth-anniversary celebrations in November 1927 and the May Day festivities of the following year. Rivera's sketches capture his reaction to these officially mandated public demonstrations—spectacles so large in scale that they defined a new type of mass political event. In January 1928, Rivera met two young American scholars—Alfred H. Barr Jr. and Jere Abbott, the future director and associate director of the Museum of Modern Art, New York, respectively—who were on the Russian leg of a European tour designed as an education in contemporary artistic developments. The three met regularly, visiting exhibitions and the studios of Moscow-based artists. The fruits of this unlikely friendship between a radical art-world celebrity and two fledgling art historians were seen in Rivera's one-man show at MoMA in the winter of 1931–32, a blockbuster that decimated the young museum's existing attendance records. In support of the exhibition, Abby Aldrich Rockefeller, a founding trustee of the Museum, purchased the sketches to help defray the cost of the artist's stay in New York. She donated the works to MoMA in 1935.