It has been over 100 years since Dr. Paul Ehrlich referred to an ideal therapeutic agent able to target and treat only a highly specific site in an organism in 1906: the so-called magic bullet . The birth of new techlogies, such as nastructures, combined with the improved kwledge on the physiology and the biochemistry at the basis of human behaviour have opened completely new trails in medicine, making the research over drug delivery one of the most vital fields of science. This book presents a timely and informative summary of the current progress in a variety of subject areas, including medicine, chemistry, and biology. This book is written by experts in the field and serves as an indispensable reference to advanced researchers. The last advances in drug delivery, including naparticles, conjugated polyphel, enhanced permeability and retention effect and also chimeric nasystems, are addressed and provided by extensive and recent literature.