John Francis Mauceri (born September 12, 1945) is an American conductor, producer, educator and writer. Since making his professional conducting debut almost half a century ago, Mauceri has appeared with most of the world's great orchestras, guest conducted at the premiere opera houses, produced and musically supervised Tony and Olivier Award-winning Broadway musicals, and served as university faculty and administrator. Through his varied career, he has taken the lead in the preservation and performance of many genres of music and has supervised/conducted important premieres by composers as diverse as Debussy, Stockhausen, Korngold, Hindemith, Bernstein, Sibelius, Ives, Elfman, and Shore. He is also a leading performer of music banned by the Third Reich and especially music of Hollywood's émigré composers.