Structural Models of the Prescription Drug Market provides a critical review of the structural econometric research focusing on the richness and complexity of the prescription drug market and discussing future research directions. Because a large number of papers rely on a Bayesian learning framework, Section 2 sets the stage by introducing the basic learning model that will be useful in later sections. Section 3 discusses the literature that makes use of individual level data. Section 4 discusses the literature that studies the product lifecycle, which primarily uses product level data. This is a broad set of articles, which includes studies focusing on persuasive versus informative effects, clinical outcomes, and publicity, as well as models related to pre-market behavior (such as R&D decisions and clinical trial outcomes). Section 5 addresses other related applications of structural models in this area, and Section 6 summarizes the key takeaways and discusses future research directions.