The last decade have seen a newfound interest in the clinical applications of the psychedelic substances; LSD, psilocybin, MDMA, DMT, ayahuasca and ketamine, which haven't been seen since the pre-prohibition days. Back then, these substances were widely used as an adjunct to psychotherapy in the treatment of severe psychiatric and psychological problems such as PTSD, depression and substance abuse. The current results are extremely promising, and i personally believe a psychedelic revolution is on the way, which will transform the field of psychiatry.There is now a push to make these substances legal medicine again, and a lot of great researchers are working to gather evidence of the safety and efficacy of these substances in various patient populations. This text aims to give an in-depth analysis of what is currently known about the possible medical applications of the psychedelics. It examines the pre- and post -prohibition medical literature as well as the manuals used in the clinical research, and will focus on the practical aspects of psychedelic-mediated therapy. It is the aim to update it on an annual basis, and in this way let it grow with the ever-expanding body of evidence, into a textbook which can be used, when/if these substances become legal medicine again. It is intended for the medial or psychological-professional, the science-minded psychonaut and the general public, who would like to know more about psychedelic substances in a serious manner.