Most drugs are analogue drugs. There are no general rules how a new drug can be discovered, nevertheless, there are some observations which help to find a new drug, and also an individual story of a drug discovery can initiate and help new discoveries. Volume 1 is the first authoritative overview of past and current strategies for successful drug development by analog generation, this unique resource spans all important drug classes and all major therapeutic fields, including histamine antagonists, ACE inhibitors, beta blockers, opioids, quinolone antibiotics, steroids and anticancer platinum compounds. Of the 19 analog classes presented in detail, 9 are described by the scientists who discoverd them. The book includes a table of the most successful drug analogs as based on the IMS ranking and compares them in terms of chemical structure, mode of action and patentability. Volume 2 was born out of a project of the IUPAC's committee on Medicinal Chemistry and Drug Development, this reference addresses past and current strategies for successful drug analog development, extending the previously published volume by nine new analog classes and eight case studies. Like its precursor, this volume also contains a general section discussing universally applicable strategies for analog discovery and development. Spanning a wide range of therapeutic fields and chemical classes, the two volumes together constitute the first systematic approach to drug analog development. Of interest to virtually every researcher working in drug discovery and pharmaceutical chemistry. Volume 3 is a continuation of the successful book series with new examples of established and recently introduced drugs. The major part of the book is written by key inventors either as a case study or a study of an analogue class. With its wide range across a variety of therapeutic fields and chemical classes, this is of interest to virtually every researcher in drug discovery and pharmaceutical chemistry, and -- together with the previous volumes -- constitutes the first systematic approach to drug analogue development.