The first aim of this book is to present all techniques devoted to non-invasive normal or diseased skin measurement. As opposed to current books which present novel methods of investigating the skin, it embraces old and new validated techniques, for all skin suborgans and functions. Each technique is discussed to help select the most appropriate one for each special case. Within each chapter, the meaning of the obtained parameters is highlighted so that the user is able to interpret the results correctly. The second aim of the book is to base the skin investigation on the physiology and anatomy. Each chapter is preceded by a compendium of current knowledge on the structure or function dealt with. Accordingly, this book is also a manual of skin physiology (21 chapters). A third aim of the book is to provide help for research purposes. This book consists of a collection of quantity of numerical data on skin anatomy and physiology. It contains a novel, and presently unique list of more than 400 physical and biological skin constants, either dimensional or functional, which are all referenced.