In my research, I examine orchestral and chamber music calling for E-flat and bass clarinet doubling to be performed by one clarinetist and analyze pieces requiring the use of both clarinets. My argument is built through an analysis of fourteen scores calling for this doubling and an accompanying catalogue of chamber and orchestral pieces that require the doubling. I examine these fourteen pieces to determine the level of virtuosity a clarinetist should have on both auxiliaries. I also interviewed and surveyed composers and clarinetists to gain a better understanding of the expectations professionals maintain regarding both E-flat and bass clarinet performance. The knowledge gained from the clarinetists shows how their proficiency on both E-flat and bass clarinet has influenced careers over the past several decades. Similarly, composers’ responses indicate their expectations for the performance of E-flat and bass clarinet by a single clarinetist in the 21st century. My research will show that the career benefits of playing both E-flat and bass clarinet, the prevalence of the doubling repertoire, and the expectations of composers for doubling clarinetists results in a novel need for the inclusion of E-flat and bass clarinet pedagogy in institutions of learning.