Maria Friderike Radner (German: [ˈʁaːdnɐ] ; 1 January 1981 – 24 March 2015) was a German contralto who performed internationally in opera and in concerts. Radner studied at the Robert Schumann Hochschule in Düsseldorf, Germany. Both Stern magazine and Munich's Abendzeitung described her as an "extremely talented interpreter of Wagner's music". Possessing the "rare pitch of a true alto", she frequently appeared as Erda in Wagner's Der Ring des Nibelungen at the Leipzig Opera, Schwertleite in Die Walküre at the Teatro Comunale di Firenze with Zubin Mehta, and in Mahler's Symphony No. 2 (the Resurrection) conducted by Antonio Pappano in Rome and Milan. Her debut at the Metropolitan Opera in 2012 in Götterdämmerung was part of that company's documentary Wagner's Dream.