This book is designed as a textbook for courses on biopharmaceutics, covering all aspects from the drug molecular level to the biological interface. The first part deals with basic concepts and applications, and the second addresses advanced topics. Topics in part 1 include absorption, solubility, drug delivery, drug release, and bioavailability. In the second, chapters include mass transfer phenomena and absorption modeling methods. Basic information, down to the explanation of the nomenclature for beginners, is provided with side notes and text boxes featuring these and other explanatory materials. Each chapter ends with an extensive list of practicing exercises, with a Solutions Manual available separately for adopting professors.