What happens when we have second thoughts about the epistemic standing of our beliefs, when we stop to check on beliefs which we have already formed or hypotheses which we have under consideration?In the essays collected in this volume, Hilary Kornblith considers this and other questions about self-knowledge and the nature of human reason.The essays draw extensively on work in social psychology to illuminate traditional epistemological issues: in contrast with traditional Cartesian approaches to these issues, Kornblith engages with empirically motivated skeptical problems, and shows how they may be constructively addressed in practical and theoretical terms.As well as bringing together ten previously published essays, the volume contains two entirely new pieces that engage with ideas of self and rational nature.Kornblith's approach lays the foundations for further development in epistemology that will benefit from advances in our understanding of human psychology.