Provides a comprehensive review of the existing research evidence concerning cannabis. In addition to examining the origins and present use of cannabis as a therapeutic and recreational substance, it looks at questions such as dependency, the relationship between hard and soft drugs and whether cannabis use should or should not be legalized. A key feature of the book is THE CANNABIS EVIDENCE AUDIT, a two year project consisting of a systematic review of the published and unpublished literature drawn from all over the world, which provides an authoritative statement of where cannabis research is today.