MGG Online - Die Musik in Geschichte und Gegenwart This link opens in a new windowDie Musik in Geschichte und Gegenwart (MGG) is a comprehensive, German-language encyclopedia offering in-depth articles on every aspect of music and related areas such as literature, philosophy, and visual arts. MGG Online contains the 2nd print edition published 1994-2008 (Ref ML100 .M92 1994) with current, continuous updates and additions.