Everyone knows that meditation is good for your health and wellbeing. However, a percentage of people practicing meditation experience psychotic breaks and related adverse mental and physical side-effects. Are these symptoms of improper practice or an unavoidable part of spiritual cultivation? While contemporary scientific literature is just beginning to document such phenomena, Buddhist communities have for centuries warned practitioners about "meditation sickness," "wind illness," "demonic attack" and other potential dangers. Due to language barriers, their important writings have remained virtually unknown in western medical, scientific, and practitioner communities. Here, for the first time, historical and contemporary teachings on the topic from around the Buddhist world have been brought together. The works not only identify these ailments as possible side-effects of meditation practice, but also explain why they arise and how they can be effectively prevented and treated. Meditation Sickness will transform the way we think about meditation in the west.