This book reminded me strongly of Walker Percy's Lancelot. A single narrator carrying a novel-length monologue. Henry is a painter who has self-exiled to a remote Island off the coast of France. He invites a former friend/art critic, William, to the island so he can paint his portrait, at William's request. Through the course of the novel Henry fills in the history of their friendship as well as the reason he agreed to paint the portrait.
An unexpected bonus to this novel was Henry's philosophy and commentary on artists. He spoke of artists in general, even though he was a painter, and talked a lot about inspiration, why artists have the personalities they do, and how art is ultimately created. It made a lot of sense and, though it was ever-present throughout the novel, never took over the plot.
Not everyone will like this book, though I think that many artists will understand it.