F. Ryerson, Jr. was an American jazz arranger and composer active primarily from the late 1940s through the 1970s. Known for his sophisticated and often intricate charts, Ryerson's style blended elements of swing and post-bop, contributing significantly to the evolution of big band writing. He was particularly adept at crafting lush voicings and dynamic ensemble passages. While specific collaborations are not widely documented, his work is believed to have influenced numerous regional and collegiate jazz ensembles, providing a foundational framework for modern jazz orchestra arrangements. His contributions helped shape the sound of mid-century large-ensemble jazz.