Hans-Erich Apostel (1901–1972) was a notable Austrian composer and music educator, primarily associated with the 20th-century classical music scene. His work is characterized by a blend of traditional classical forms and modern techniques, particularly influenced by atonality and serialism. Apostel's notable works include his symphonies, chamber music, and vocal compositions, with pieces such as the "Symphony No. 1" and "Concerto for Piano and Orchestra" garnering attention for their innovative structures and rich harmonic language. He also composed operas, including "Die Fledermaus" and "Der Turm," which reflect his interest in dramatic expression. As a professor at the University of Music and Performing Arts in Vienna, Apostel significantly impacted the education of future generations of composers and musicians. His contributions to music theory and practice helped to shape the modern Austrian musical landscape, influencing both his students and contemporaries in the realm of contemporary classical music.