In view of the rapid growth in both experimental and theoretical studies of multiphoton processes and multiphoton spectroscopy of atoms, ions and molecules in chemistry, physics, biology, material sciences, etc., it is desirable to publish an Advanced Series that contains review papers readable not only by active researchers in these areas, but also by those who are not experts in the field but who intend to enter the field. The present series attempts to serve this purpose. Each review article is written in a self-contained manner by the experts in the area so that the readers can grasp the knowledge in the area without too much preparation.The topics covered in this volume include ?Ultrafast Photochemical Dynamics in Solution Studied by Femtosecond Time-Resolved Fluorescence Spectroscopy: Involvement of Highly Excited States?, ?Spectral Selective Studies of Molecular Doped Solids and Applications?, ?From Multiphoton to Tunnel Ionization?, ?Cluster Dynamics in Intense Laser Fields?, and ?Molecular Theory of Sum-Frequency Generation and its Application to Study Molecular Chirality?. It is hoped that the collection of topics in this volume will be useful not only to active researchers but also to other scientists in biology, chemistry, materials science and physics.This book has been selected for coverage in: ? CC / Physical, Chemical & Earth Sciences? Index to Scientific Book Contents? (ISBC)