When considering our first-person knowledge of our own minds, whether with regard to immediate awareness of a sensory experience, reflection upon one's own beliefs or desires, deliberation concerning one's character, or metaphysical soul-searching about one's ultimate nature, we commonly appeal to the concept of introspection. But what exactly are we talking about when we speak of introspection? Do we literally perceive our own mental states, as the term seems to suggest, or are there other processes at work in our ability to know our own minds? Can introspection be trusted as a viable or even privileged source of knowledge, as many have claimed and many others have simply assumed, or are there significant barriers, problems, and limits regarding what we can know about our own minds from our own first-person perspective? This book offers a pluralistic framework for understanding these issues regarding the nature and epistemic properties of introspection. At the core of this framework is the idea that introspection is a multi-faceted phenomenon that cannot be limited to a single cognitive mechanism or epistemic characterization. There are many different ways in which we engage in introspection and, correspondingly, a variety of different epistemic dimensions involved in our first-person understanding of our own minds. Through presentation and analysis of these various aspects of introspection, I illustrate how we know, and sometimes fail to know, our own minds.