This volume brings together recent work on the nature of belief, imagination, and delusion. Whilst philosophers of mind and epistemology employ notions of belief and imagination in their theorizing, parallel work seeking to make these notions more precise continues. Delusions are standardly taken to be bizarre beliefs occurring in the clinical population, which do not respond to evidence. The purpose of this collection of essays is to get clearer on the nature of belief and imagination, the ways in which they relate to one another, and how they might be integrated into accounts of delusional belief formation. The jumping off point is the idea that recent work in philosophy of mind and epistemology which has sought to characterise the nature of belief and imagination allows us to formulate the issues with new precision, by, for example, drawing on work concerning how imagination is involved in delusion formation, or work concerning how to properly distinguish imagination from belief. The volume also considers questions concerning imagination's architecture, the role of metacognitive error in our mental lives, how best to understand delusional experience, and the relationship between delusion and evidence. The contributors are ideally placed to explore these issues, both individually and as a collective. With interests spanning different disciplines (philosophy, psychology, cognitive science), and approaches (theoretical, empirically informed), the result is a rich and varied collection of insights.