Erling E. Guldbrandsen is professor at the Department of Musicology, University of Oslo where he leads the research group, '20/21 - Musical Trajectories Today'. He has carried out research at IRCAM (Paris) and at the Paul Sacher Foundation (Basel) and received the King's Gold Medal for his work on Boulez. His 2006 article on Mahler and Boulez was awarded the Norwegian prize, 'Scientific Article of the Year'. He has published widely on Wagner and musical drama, musical modernism, music history, analysis, performance practice and aesthetic experience. Julian Johnson is Regius Professor of Music at Royal Holloway, University of London. He has written five books, including Webern and the Transformation of Nature (Cambridge, 1999) and Mahler's Voices (2009). His most recent book, Out of Time: Music and the Making of Modernity (2015), considers music's constitutive relation to modernity from the sixteenth century to the present. In 2005, he was awarded the Dent Medal of the RMA for 'outstanding contributions to musicology' and, in 2013, became the first holder of the Diamond Jubilee Regius Chair of Music.