This book reviews the imaging features associated with selected classes of pharmaceuticals and drugs on brain, head and neck, and spine and explains the implications of the imaging findings for the neuroradiologist and the clinician. Some agents produce characteristic abnormalities with distinctive imaging features, while others have a spectrum of manifestations on imaging. Still further agents produce rather nonspecific changes on imaging, requiring a differential diagnosis. In this book, informative cases are depicted by rich images, with concise accompanying explanatory text that reviews the class of agent and the mechanism of action and discusses image interpretation and its significance.