Frederick, an American jazz arranger active from the 1940s through the 1960s, was a significant, albeit often uncredited, contributor to the big band sound. Known for his sophisticated harmonic voicings and intricate counterpoint, Frederick's arrangements blended swing era exuberance with nascent bebop sensibilities. While he primarily worked as a staff arranger for several prominent record labels, his distinctive touch can be heard on recordings by artists such as Count Basie and Sarah Vaughan. His innovative use of woodwind sections and brass fanfares helped define the evolving sound of large jazz ensembles during a pivotal period in the genre's history.