This graduate textbook is meant primarily for those interested in physical organic chemistry and in organic photochemistry. It is a significantly up-
dated translation of Lichtabsorption und Photochemie organischer Mole-
kiile, published by VCH in 1989. It provides a qualitative description of elec-
tronic excitation in organic molecules and of the associated spectroscopy,
photophysics, and photochemistry. The text is nonmathematical and only
assumes the knowledge of basic organic chemistry and spectroscopy, and
rudimentary knowledge of quantum chemistry, particularly molecular or-
bital theory. A suitable introduction to quantum chemistry for a German-
reading neophyte is Elektronenstruktur organischer Molekiile, by Martin
Klessinger, published by VCH in 1982 as a volume of the series, Physikal-
ische Organische Chemie. The present textbook emphasizes the use of sim-
ple qualitative models for developing an intuitive feeling for the course of
photophysical and photochemical processes in terms of potential energy hy-
persurfaces. Special attention is paid to recent developments, particularly
to the role of conical intersections. In emphasizing the qualitative aspects of
photochemical theory, the present text is complementary to the more math-
ematical specialized monograph by Josef Michl and Vlasta Bonai-Kou-
tecky, Electronic Aspects of Organic Photochemistry, published by Wiley in
1990.