Toxic plants have been studied, cultivated, and deliberately kept for centuries — by physicians, poisoners, midwives, cunning folk, and anyone who understood that the line between medicine and poison was a matter of dose rather than intent. Many of the most dangerous plants in this archive are also the most pharmacologically significant, their alkaloids still present in modern medicine under different names. Their history belongs not only to the dangerous but to everyone who learned to work carefully with difficult things.