What is the theme in A Portrait of the Artist as a Young Man by James Joyce?

Consciousness is a main theme in the book. In literary terms, one of the revolutionary aspects of A Portrait of the Artist as a Young Man is the fact that there is no actual plot to the book. Instead, the progress of the novel is organized around the growing consciousness of the central character, Stephen Dedalus. His consciousness of the world around him is an ongoing theme and is developed differently in each of the book's five chapters. He experiences many types and levels of consciousness. Moreover, Joyce uses a highly original "stream-of-consciousness" technique to render Stephen's thoughts and experiences.