The book presents novel carrier systems for the targeted and controlled drug delivery for the treatment of various diseases which are difficult to be treated with conventional drug delivery systems like cancer, autoimmune disorders, and emerging infectious diseases. It also reviews the origins and applications of stimuli-responsive polymer systems and polymer therapeutics such as polymer-protein and polymer-drug conjugates. The book also explores the potential applications of the parenteral route of administration for the delivery of active pharmaceutical substances with a narrow therapeutic index and poor bioavailability. Further, the book presents common routes of administration for the systemic delivery of peptides and proteins. It also examines the applications of various implantable systems in drug delivery. The book also covers the important colloidal drug delivery systems, including liposomes and niosomes and solid lipid nanoparticles, and nanostructured lipid carriers. Towards,the end, the book discusses the therapeutic potential of biodegradable polymeric nanoparticles for controlled drug delivery. Authoritative and thorough, this book is a valuable resource for researchers working on a multidisciplinary approach to employing drug delivery systems.