"It was a remarkable 32 years ago that the first edition of Strom's Pharmacoepidemiology was published. The preface to that book stated that pharmacoepidemiology was a new field with a new generation of pharmacoepidemiologists arising to join the field's few pioneers. Over the ensuing 32 years, the field indeed has grown and no longer deserves to be called "new." Many of those "new generation" scientists (including two of the editors of this book) are now "middle-aged" pharmacoepidemiologists. Despite its relatively brief academic life, a short history of pharmacoepidemiology and review of its current state will set the stage for the purpose of this textbook. Pharmacoepidemiology originally arose from the union of the fields of clinical pharmacology and epidemiology. Pharmacoepidemiology studies the use of and the effects of medical products in large numbers of people and applies the methods of epidemiology to the content area of clinical pharmacology. This field represents the science underlying postmarketing medical product surveillance, studies of the effects of medical products (i.e., drugs, biologicals, devices) performed after a product has been approved for use. In recent years, pharmacoepidemiology has expanded to include many other types of studies, as well"--