This study documents the career of Joseph Eger (b. 1920), who had a short but remarkable playing career in the 1940s, 1950s and early 1960s. Eger toured the United States and Britain as a soloist with his own group, even trading tours with the legendary British hornist, Dennis Brain. He recorded a brilliant solo album, transcribed or arranged several solos for horn, and premiered compositions now standard in the horn repertoire. He served as Principal Horn of the New York Philharmonic, Los Angeles Philharmonic, and the National Symphony. Despite his illustrious career as a hornist, many horn players today do not recognize his name. While Eger was a renowned horn soloist in the middle of the twentieth century, he all but disappeared as a hornist, refocused his career, and reemerged as a conductor, social activist, and author. This dissertation seeks to be the long-overdue comprehensive documentation of Eger's career as the first American horn soloist and his contributions to the world of horn playing. First, a biography of Eger is presented, focusing especially on his education and career as an orchestral player, soloist, and recording artist, including its intersections with the lives of many prominent musicians and personalities of the twentieth century. A personal interview provided most of this information. An examination of what is perhaps Eger's greatest and most lasting contribution, his solo album, Around the Horn, will follow. A discussion of this recording and his Grammy-nominated chamber music album will provide insight into the high quality of his horn playing and the breadth of his repertoire. Finally, Eger's transcriptions and editions of pieces for solo horn and the pieces that were premiered or composed for him will be listed and discussed.