This thesis focuses on Sondheim’s 1979 work, Sweeney Todd, the Demon Barber of Fleet Street (referred to simply as Sweeney Todd from now on), and serves as a brief study of the piece, examining its musical and dramatic significance. Sondheim’s score for Sweeney is one of his richest and most complicated, while the subject matter provides its own weight as an unusual plot for a Broadway musical. Rather than focusing on any one particular feature of the work, the thesis delves into various aspects of music, text, and character, and brings to light some of Sondheim’s most innovative compositional and textual devices. The controversial plot, rich book and stylistically interdependent almost sung-through score gives the work a unique quality that separates it from the other titles in Sondheim’s canon, and overall, from other works in the broader musical theatre catalogue. Sondheim’s appreciation in academia by both musicologists and theatre scholars has taken quite some time to develop because of the apparent stigma attached to the form. This dissertation ultimately responds to both the attention and the neglect given to this composer in the world of musicology.