Book excerpt: How do you know anything is true? What relation is there between my psyche and your psyche, does one exist? Can we doubt everything or are some things indubitable? What does Jung have to say about body and psyche, body and mind? Cartesian Philosophy and the Flesh is an analysis and critique of interpretations of Cartesian philosophy in analytical psychology. It focuses on readings of Descartes that have important implications for understanding Jung, and analytical and existential psychology generally. Frances Gray's book raises questions about the 'place' of the body in a theory of the human psyche and about what kind of psyche, if any, is essential to concepts of human being. Gray claims that the debates around Descartes and metaphysical dualism have been oversimplified and that this has had a profound effect on conceptualizing an on-going relation between psyche and body. The book also explores the relationship between Jung's conception of the phenomenological standpoint and that of Edmund Husserl and Maurice Merleau-Ponty. Cartesian Philosophy and Flesh brings together Descartes’ idea of self-interrogation and self-reflection and Jung's project in The Red Book, the practice of spiritual exercises is the underpinning orientation of both men. It recommends similar practices to anyone interested in the truths of their own living. Gray’s book will be of interest to Jung scholars, and those with an interest in Jungian studies, Analytical Psychologists and Philosophers.