Joni Mitchell is one of the most outstanding singer-songwriters with regard to her great body of work, stylistic diversity and poetic expression. This thesis investigates Joni Mitchells musical and lyrical development in the 60s and 70s, her most formative phase. It discusses the problems of popular music analysis and argues to include singer-songwriters in this genre, although they somehow fall in between high and popular art. As pop songs are experienced via several dimensions, usually the lyrical and musical being the most prominent ones, they are an intermedial phenomenon. In this thesis, a songs intermediality is acknowledged and the interplay between music and words is investigated, while the main attention is put on the latter. The analyses show, for example, how the harmonies or the melody line support the message of the words. In a separate chapter, the artist Joni Mitchell is introduced by outlining her life and career and describing her musical and poetic style, as well as her passion for painting. The main body of the thesis focuses on the analysis of six representative songs by Joni Mitchell. After giving an introduction to her musical and poetic development and an overview of her albums, each of these hits is analyzed separately. The songs are divided into three periods, starting with her folk breakthrough in the 60s, which is her most folk-influenced period, followed by the Blue Period in the early 70s, in which she produced her most personal songs. In the third period, during the late 70s, Joni Mitchell ventures to explore jazz. The analyses elucidate Mitchells most prominent themes and how they are connected with her life. She repeatedly addresses the themes of love, freedom, traveling and duality in her songs, most distinctly her desire for personal freedom and independence. Furthermore, the analyses outline the increasing complexity in Mitchells songs in both the music and the lyrics, as she keeps innovating and re-inventing her style.