Judith Weir (b. 1954) composed King Harald’s Saga: Grand Opera in Three Acts for Unaccompanied Solo Soprano Singing Eight Rôles (1979) for radio broadcast. She wrote the libretto for the opera based on Snorri Sturluson’s book, King Harald’s Saga. This opera illustrates Weir’s remarkable compositional style, including her treatment of the libretto in narrative style and her representation of multiple characters by one singer. Despite Weir’s fame as an opera composer, King Harald’s Saga is rarely performed owing to three major musical and performing challenges. These challenges are performer’s ability to delineate eight separate characters (dramatic challenges), to sing wide leaps and long melismas (vocal challenges), and to perform a cappella with wide leaps and complex rhythms (musical challenges). This dissertation presents a performance guide for the soprano addressing these three challenges and suggesting possible solutions. Such a guide will assist the soprano in preparing and performing this grand opera, which thus far has not received the due attention and appreciation of either performers or audiences.