Studies of environmental conditions have become more and more important for oUf knowledge about the complex processes resulting from natural and man-made influences on OUf environment. During recent years new analytical techniques have been developed that are mainly based on laser spectroscopy. They are not only more sensitive and reach lower detection limits but they also give more de tailed information on the species under investigation and their interactions with the environment. They therefore can considerably deepen OUf understanding of correlations between different processes and their causes, which is the precondi tion for avoiding ecological damage and for strengthening effective engagement in environmental protection. Also in life sciences revolutionary new techniques for diagnostics have been in troduced which allow a thorough investigation of biological processes in plants and their dependence on environmental conditions. In particular for medical appli cations these new mainly non-invasive techniques have influenced medical diag nostics and treatment considerably. This book deals with these very interesting interdisciplinary subjects which demand experience and knowledge about both fields: the basic physics of the de tection techniques and the relevant problems in environmental and life sciences. Therefore authors from a broad area of fundamental and applied research have contributed to this book, which is organized in 4 sections: Remote sensing of the atmosphere, detection techniques for liquid and solid samples, applications to gaseous substances and aerosols and finally applications in biology and medicine.