The definitive story of cannabis, from its evolution and biological quirks to its role in human history In this entertaining natural history, Rob DeSalle provides a glimpse into the biological world through the lens of the marijuana plant. A close relative of hops with a surprising place in the botanical tree of life, cannabis has a unique life cycle, has evolved pathways for over four hundred compounds, and makes one thousand or so different chemicals that are stored in its tissues-some of which are the basis of its famed psychoactive properties. With his scientist's perspective on this well-known and controversial plant, DeSalle considers taxonomy, systematics, evolution, human physiology and neurobiology, and cultural issues. He discusses the plant's complicated reproductive strategies; considers ancient arthropod-cannabis associations from South Asia; and offers a nuanced cultural history that extends from the first evidence of smoking cannabis more than two thousand years ago to the current debates over legalization. Engaging and extensively researched, with illustrations by Patricia J. Wynne, this is a vital resource for cannabis enthusiasts and anyone curious about the science behind this infamous "weed."