This collection of essays delves into some of the strangest and most profound aspects of the psychedelic experience, such as seeing the self as an illusion, feelings of deep insight, the sublime (fear mixed with wonder), encounters with DMT entities, déjà vu, and existential joy. Drawing on research and theories from a variety of disciplines, Sam Woolfe reflects on the ways that altered states may inform our understanding of consciousness, the self, and reality. Particular attention is paid to the philosophy of psychedelics, with the aim of clarifying altered states through the lenses of metaphysics, philosophy of mind, epistemology, aesthetics, existentialism, and Buddhism. In these essays, Woolfe balances open-mindedness with a critical and sceptical perspective - he believes that this approach is necessary when examining psychedelic consciousness.