The book is an artist's novel that not only talks about the art of its hero but can also convincingly demonstrate it in various ways. A man, an exiled Russian, attempts to reconstruct the true life of his half-brother, the writer Sebastian Knight. As he sets to work, he has nothing but a few childhood memories, some sparse information, an intimate knowledge of Knight's books, and a great deal of admiration, love, and enthusiasm. His search for the true life of his brother forms the content of the book.