Leo Treitler, Distinguished Professor of Music at the City University of New York, is the author of Music and the Historical Imagination, as well as other books and articles on music historiography and medieval music. Gary Tomlinson taught at the University of Pennsylvania before moving to Yale University in 2011, where he is now the John Hay Whitney Professor and Director of the Whitney Humanities Center. A former MacArthur Fellow, he has authored books on Claudio Monteverdi, Renaissance musical culture, the opera, and the singing rituals of the Aztecs and Incas. His latest book, A Million Years in Music, describes the evolutionary emergence of music. Tomlinson and Kerman worked together on five editions of Listen before Joseph Kerman died in 2014 as this edition went to press, just shy of his ninetieth birthday. Teaching was at the heart and soul of Kerman's musical career, and it remains so in Tomlinson's. Between them, their wide-ranging course offerings have encompassed harmony and ear-training, opera, world music, popular music, and interdisciplinary studies, including seminars in music history, criticism, anthropology, and—many times over—Introduction to Music for non-majors.