Fluorescent excitation analysis (FEA) is a technique that has been utilized for some time in physics. An increasing number of biomedical applications for FEA have been reported in recent year: it is becoming the assay method of choice in many areas of research and clinical practice. The purpose of this volume is to acquaint the interest physician or physicist with the basic principles and instrumentation relevant for FEA, as well as some present and future biomedical applications.