This book provides a multidisciplinary overview to the application of high order derivative spectrophotometry and Electron Spin Resonance (ESR) spectroscopy in biology and ecology. The characteristics of the principle methods as well as the generation of reliable spectra are discussed in general terms allowing the reader to gain an idea of these methods’ potentials. Furthermore the authors give an extended overview to the spectroscopic and spectro-photometric analysis of specific biological materials. This volume is a well condensed description of an analytical method and a clear review to its application in biology and related fields and an essential tool for researchers who are new in the field of spectroscopic methods and their applications in the life sciences.