Drug delivery system refers to the creation of a device which enables a therapeutic substance to reach a selected location in the human body without targeting the healthy tissues, cells and organs. It is a wide area of research which is related to the development of various new carrier systems and materials to be used in the delivery of drugs for efficient treatment. The novel systems of drug delivery are focused on providing sustained drug delivery with better body distribution, avoidance of drug clearance, and drug protection from harsh external environment. Furthermore, it comprises of polymeric, lipidic and proteic technologies. The evolution of nanomaterials for drug delivery, known as nano-drug delivery systems (NDDSs), provides the opportunity to avoid the side effects of systemic drug administration and injury caused by the removal of tumors. This book on advances in drug delivery is a collective contribution of a renowned group of international experts. It traces significant advances in drug delivery systems. The book is an invaluable source of reference for medical practitioners, students, scientists, and researchers.