Sumler, a University of Colorado lecturer, goes well beyond Greece and Rome, where cannabis use was actually limited. His book covers many views on cannabis (Cannabis sativa) and its use all over the ancient world. He has in-depth discussion on how it was shared between different cultures. What results is quite a variety of interesting comparisons covering practical cures for physical problems like pain along with more mystical uses. I have to admit a few of these are an herbal stretch for me, like a theory that references to gentle, demulcent marshmallow (Althea officinalis) root—used in cough syrup—might refer to cannabis. However, this is an example of what makes this such a thought-provoking and interesting book.