S. Spiegl, a prominent figure in mid-20th century jazz, was an American arranger whose innovative orchestrations significantly shaped the sound of big band music. Known for his sophisticated harmonic language and intricate counterpoint, Spiegl's work often blended elements of swing with nascent bebop sensibilities. He notably collaborated with leading ensembles, crafting arrangements that showcased their virtuosity and expanded the expressive potential of the jazz orchestra. His contributions are particularly recognized for their influence on brass sections, introducing fresh voicings and rhythmic complexities that became hallmarks of the era's most dynamic bands.