"Might this be a dream?" In this book, distinguished philosopher J. J. Valberg approaches the familiar question about dream and reality by seeking to identify its subject matter: what is it that would be the dream if "this" were a dream? It turns out to be a subject matter that contains the whole of the world, space, and time but which, like consciousness for Sartre, is nothing "in itself." This subject matter, the "personal horizon," lies at the heart of the main topics--the first person, the self, and the self in time--explored at length in the book. The personal horizon is, Valberg contends, the subject matter whose center each of us occupies, and which for each of us ceases with death. This ceasing to be presents itself solipsistically not just as the end of everything "for me" but as the end of everything absolutely. Yet since it is the same for everyone, this cannot be. Death thus confronts us with an impossible fact: something that cannot be but will be. The puzzle about death is one of several extraphilosophical puzzles about the self that Valberg discusses, puzzles that can trouble everyday consciousness without any contribution from philosophy. Nor can philosophy resolve the puzzles. Its task is to get to the bottom of them, and in this respect to understand ourselves--a task philosophy has always set itself.