Plants, which make thousands of complex natural products, are outstanding chemists. Through the concerted action of enzymes that are assembled into metabolic pathways, nature creates enormous chemical complexity from simple starting materials. This talk will highlight the discovery process for enzymes that catalyze unusual or unprecedented enzymatic transformations, mechanistic and structural characterization of these enzymes, and methods by which these enzymes can be harnessed for metabolic engineering to generate pharmacological important compounds. A variety of different plants and molecules are used for these studies, most notably the monoterpene indole alkaloids and the monoterpenes known as iridoids.