Accounts in Drug Discovery describes recent case studies in medicinal chemistry with a particular emphasis on how the inevitable problems that arise during any project can be surmounted or overcome. The Editors cover a wide range of therapeutic areas and medicinal chemistry strategies, including lead optimization starting from high throughput screening hits as well as rational, structure-based design. The chapters include follow-ons and next generation compounds that aim to improve upon first generation agents. This volume surveys the range of challenges commonly faced by medicinal chemistry researchers, including the optimization of metabolism and pharmacokinetics, toxicology, pharmaceutics and pharmacology, including proof of concept in the clinic for novel biological targets. The case studies include medicinal chemistry stories on recently approved and marketed drugs, but also chronicle near-misses , i.e., exemplary compounds that may have proceeded well into the clinic but for various reasons did not result in a successful registration. As the vast majority of projects fail prior to registration, much can be learned from such narratives. By sharing a wide range of drug discovery experiences and information across the community of medicinal chemists in both industry and academia, we believe that these accounts will provide insights into the art of medicinal chemistry as it is currently practiced and will help to serve the needs of active medicinal chemists.