The focus of this book is on sonophoresis for dermal delivery of drugs. The ultrasound, an efficient physical enhancer, has been applied and studied in sonophoresis for the delivery of therapeutic moieties through dermis. Here, mode of application, physical parameters, mechanism and safety issues of sonophoresis in addition to its transdermal and clinical studies have been discussed. Synergistic action of sonophoresis with other enhancement techniques is also included here.