Original signatures of Shostakovich, Vladigerov, Kabalevski, Dzerzhinsky and 11 additional Russian, Slavic and European classical composers, variously signed in black ink, blue ink and pencil on a picture postcard mailed from Prague to Chicago on May 5, 1957, during a meeting of the Union of Soviet Composers occuring at Prague Spring 1957. The identified signatures include: Slavko (Zlatic); Pancho Vladigerov; D(mitri) Kabalevski; D(mitri) Shostakovich; Lyubo (Lyubomir) Pipkov; Jean-Louis Martinet; Cesare Valabrega; Witold Lutoslavski; Tadeusz Sawicki; Alexander Moyzes; Louis Durey; Ivan (Ivanovich) Dzerzhinsky. Obtained by composer and conductor Slavko Zlatic, a host of the conference, in homage to his cousin Boris Zlatich (the addressee), a noted young American concert violinist. Very fine.