Nocturnal op. 70 is one of the most important large-scale works written for guitar in the twentieth century. Brief biographical data and some background information on Nocturnal show how it exemplifies Britten's compositional approach. The focus of the analysis is on three structural aspects: the rhythmic, the intervallic, and the aspect of underlying pitch patterns. The rhythmic analysis discusses the distortion of rhythmic patterns by the use of compression, expansion, elisions, syncopation, and rhythmic dissonance. The pitch set analysis discusses the intervallic character of the work, identifying and correlating set types as they form networks of relationship. The reductive analysis discusses the underlying connections of focal pitches in the linear material of Nocturnal. The conclusion then correlates the results of the preceding analyses, discussing the large-scale unfolding of the form in Nocturnal.