Alfred Einstein (December 30, 1880 – February 13, 1952) was a German-American musicologist and music editor. He is best known for being the editor of the first major revision of the Köchel catalogue, which was published in the year 1936. The Köchel catalogue is the extensive catalogue of the works of Wolfgang Amadeus Mozart. Einstein was known to have had such a depth of familiarity with Mozart that he had something pertinent to say about every piece Mozart wrote.
Einstein was born in Munich. Though he originally studied law, he quickly realized his principal love was music, and he acquired a doctorate at Munich University, focusing on instrumental music of the late Renaissance and early Baroque eras, in particular music for the viola da gamba. In 1918 he became the first editor of the Zeitschrift für Musikwissenschaft; slightly later he became music critic for the Münchner Post; and in 1927 became music critic for the Berliner Tageblatt. In this period he was also a friend of the composer Heinrich Kaspar Schmid in Munich and Augsburg. In 1933, after Hitler's rise to power, he left Nazi Germany, moving first to London, then to Italy, and finally to the United States in 1939, where he held a succession of teaching posts at universities including Smith College, Columbia University, Princeton University, the University of Michigan, and the Hartt School of Music in Hartford, Connecticut.
Einstein not only researched and wrote detailed works on specific topics, but wrote popular histories of music, including the Short History of Music (1917), and Greatness in Music (1941). In particular, due to his depth of familiarity with Mozart, he published an important and extensive revision of the Köchel catalogue of Mozart's music (1936). It is this work for which Einstein is most well known. Einstein also published a comprehensive, three-volume set The Italian Madrigal (1949) on the secular Italian form, the first detailed study of the subject. His 1945 volume Mozart: His Character, His Work was an influential study of Mozart and is perhaps his best known book.