The first three volumes in this series were mainly devoted to applications of Synchrotron Radiation in various fields of physics and chemistry. Volume 4 covers in a self-contained manner the properties of sources, elements of instrumentation and applications to biological and medical research. The exception confirming the rule is EXAFS where it was felt that this topic at the border between inorganic chemistry and biochemistry was adequately covered in previous volumes and in several recently published textbooks. Each chapter provides an introduction for newcomers as well as a reference for more advanced researchers. In conclusion this is a unique book providing a comprehensive overview of the use of S.-R. in biology and medicine.