Arthur Willard Pryor (1870-1942) was an American trombonist, composer, and bandleader, primarily associated with the early 20th-century concert and brass band music. He was a prominent figure in the development of trombone performance and was known for his virtuosic playing style, which helped elevate the status of the instrument within concert bands. Pryor served as the principal trombonist for the Sousa Band, one of the most famous concert bands of the era, from 1892 until 1903. During his tenure, he composed over 100 works, with notable pieces including "The Whistler and His Dog" and "Blue Bells of Scotland," which showcased both his compositional talent and trombone prowess. His contributions to music extended beyond performance; he was influential in popularizing the trombone in various genres, including military and circus bands. Pryor's legacy persists in the trombone repertoire and through his innovative techniques, which inspired future generations of musicians. His work paved the way for the trombone as a solo instrument in concert and jazz settings, marking a significant impact on American music.