This thesis reexamines the forty short texts Joyce called “epiphanies” (c.1901-04) and the use he made of them in his subsequent work, arguing that Joyce's “earliest important literary compositions” remain important until his last, Finnegans Wake. To the extent that Joyce's oeuvre can be considered as “one great work,” the epiphanies lie at its origin, both temporally and as an originary stage of development. Thus, I argue that the genesis of Stephen Hero and Portrait can be traced back to the epiphanies, which form the “principal building blocks” of his novels; as an ensemble of discrete, but interconnected texts, their structure also bears comparison to Dubliners, Ulysses and the Wake. Building on Litz's claim that the two types of epiphany, dramatic and lyrical, represent “the twin poles of Joyce's art,” I trace Joyce's stylistic development through the epiphanies, Dubliners, Portrait and Ulysses, showing how Joyce's linguistic experimentation points to silence and repetition as the fundamental charge of each pole. This nucleus originates in Joyce's epiphanies, but its semantic energy sets off a chain reaction that leads to Finnegans Wake. At the same time, Joyce's texts are increasingly self-reflexive, ensuring that their physical properties are always apparent: materiality and reflexivity manifest two sides of the same sign. To put this into context, whilst Joyce maintains a stronger connection to Classical and biblical theophanies than has hitherto been recognised, his epiphanies differ from traditional or Romantic revelations to the extent that they are textual manifestations. Indeed, I argue that Joyce's epiphanies are purely linguistic phenomena, whose defining characteristics – silence, repetition, materiality and self-reflexivity – show forth the constituent features of language.