It is the expectation of the editors that this volume will become a gold standard book - the only singular source of current and cutting-edge information for all those working with drug abusing or addicted patients or for those interested in this topic from other research perspectives. In brief, Drug Abuse and Addiction in Medical Illness: Causes, Consequences, and Treatment will contain 62 chapters covering drugs of abuse and how they play a role in a wide range of medical illnesses. That is, the volume will discuss how, for some diseases, drug abuse will cause or enhance the progress of that disease/disorder, while other diseases may result in or enhance drug abuse. The chapters in that section will thus deal with this crucial, bi-directional relationship. Leading experts in the field of addiction throughout the world will contribute to the volume. This means the designed content will cover virtually every core, as well as contemporary, topic in the subject area, from the established theories to the most modern research and development in the field of drug abuse and addiction. Thus, once completed, the volume will be a first of its kind book, rich yet comprehensive and focused (specifically to the designated area), and will address the needs of the very active theoretical, basic, and clinical research in the field.