B. Hammack, an American jazz arranger active primarily from the 1950s through the 1970s, was a significant figure in the evolution of big band jazz. Known for his sophisticated harmonic language and innovative voicings, Hammack's arrangements blended traditional swing elements with emerging bebop sensibilities. He notably collaborated with prominent bandleaders such as Count Basie and Stan Kenton, contributing charts that showcased his meticulous attention to detail and his ability to craft dynamic, engaging musical narratives. Hammack's work expanded the expressive capabilities of the jazz orchestra, influencing subsequent generations of arrangers and enriching the big band repertoire with his distinctive sound.