Photochemistry studies this subject which sits in the broad filed of chemistry. The text describes the 'new' chemistry that follows the absorption of light, and explains how light has this extraordinary influence on chemical behaviour. Examples of established principles are presented examining the way in which life and the other natural processes depend on photochemistry, and also how photochemistry can be used in a variety of applications. Chapters focus on chemical change, photophysics, photochemical kinetics, photochemistry in nature, and applied photochemistry.