After an introduction describing our knowledge of Joyce's reading and reviewing the critical discussion of Joyce and sexuality, the thesis falls into five chapters. In the first chapter I outline contemporary debates about marriage and divorce. The facts of Joyce's life suggest a participation in these debates and I describe and discuss his reading on marriage law, adultery and Free Love and the contribution made by such issues to his fiction. In the second chapter I define the notion of "sexuality" as an entity separate from reproduction which is essential to twentieth century liberalism and argue that Joyce arrived at a modern position through his reading of some nineteenth century and theological works on the subject. In the third chapter I discuss Joyce's problematic relationship to feminism. His publication was aided to a surprising degree with the help of feministically conscious women and his writing displays a highly sophisticated interest in sexual identity and role, in female dominance and in prostitution. The final chapters discuss Joyce's conflict with the censorship of sexual material in literature and attempt to show that writing about sexuality was fundamental to Joyce's own literary critical notions and not as incidental or subsidiary to his achievement as has often been supposed. ~ This entails both a re-examination of Joyce's practical aesthetic priorities and of other less apparently literary motivations for his work. In conclusion I discuss wider implications of the critical method here adopted of discussing an author's work primarily in relation to the books that he read. With regard to recent theories of "intertextuality" I suggest some relevant forms of relationship between texts and argue for the value of the term "pretext" in understanding the role of Joyce's reading in this field.