Erik William Gustav Leidzen (1900-1989) was a notable American composer, arranger, and conductor, primarily recognized for his contributions to the band and concert music genres. His work spanned various styles, but he is best known for his contributions to the wind band repertoire and his arrangements of classical and popular music for concert bands. Leidzen's notable works include original compositions such as "Swan Lake Suite" and "The Man Who Knew Too Much," as well as numerous arrangements of classical pieces for concert band, which helped to popularize classical music within band settings. He also arranged music for orchestras and was influential in writing for the American military bands. Leidzen’s impact on music lies in his ability to bridge classical music with the wind band idiom, making it accessible and appealing to a broader audience. His arrangements are still widely performed and studied in music education programs, solidifying his legacy in the wind band community. His work contributed to the development of the concert band as a legitimate performance ensemble, influencing generations of musicians and composers in the genre.