The chapters of this volume represent the invited papers delivered at the 3rd International Conference on Multiphoton Processes (ICOMP III) held in Iraklion, Crete, Greece, September 5-11, 1984. The invited papers at a conference like ICOMP cannot possibly cover the whole field which has grown to immense proportions in recent years, overlapping with such diverse areas as atomic and molecular spectroscopy, plasma physics, nonlinear optics, quantum optics, etc. We believe these contributions represent that part of the research activity which has been attracting the most interest in the past year or so, as well as reviews of some of the more established topics. Even within this scope, and given the confines imposed by the fi­ nite duration of a conference, important and timely topics are inevitably left out. But then, there will be ICOMP IV. The collection of articles in this volume, combined with extensive ref­ erences to related work given by the authors, should provide an introduc­ tion to the major problems of the field and its state of the art. The chapters have been arranged according to thematic proximity, beginning with atoms, and continuing on with molecules and surfaces. This classi­ fication, however, would not cover all the subject matter even within the limited scope of the conference and of this volume.

I Multiphoton Processes in Atoms.- Multiphoton Ionisation of Atoms in Strong Fields.- Multiphoton Transitions in the Ionization Continuum of Atoms.- Multiply Charged Ions Produced in Multiphoton Ionization of Rare Gas Atoms.- Studies of Collision-Free Nonlinear Processes in the Ultraviolet Range.- Multiphoton Excitation of Doubly Excited States of Two-Electron Atoms.- Multiphoton Ionization Via Rydberg States and Effects of High Laser Intensity.- Effects of dc Electric Fields on Multiphoton Ionization Spectra in Cesium.- II Field Fluctuations and Collisions in Multiphoton Processes.- Field Fluctuations and Multiphoton Processes.- Two-Photon Absorption from a Phase Diffusing Laser Field.- Electron Scattering in the Presence of Laser Radiation.- Multiphoton Effects During Collisions.- Pressure Effects in the Multiphoton Ionization of Atoms and Molecules.- III Multiphoton Processes in Molecules and Surfaces.- Infrared Multiphoton Absorption and Decomposition.- A Physical Explanation of Quasiperiodic Motion and the Onset of Chaos in Nonlinear Systems.- Theoretical Studies of Resonantly Enhanced Multiphoton Ionization Processes in Molecules.- Photoionization of Excited Molecular States.- Resonant Two-Photon Ionization and Dissociation of the Hydrogen Atom and Molecule.- Multiphoton Ionization Photoelectron Spectroscopy for Excited-State Atoms and Molecules.- 2-Step Photoionization of Benzene: Mechanism and Spectoscopy.- Multiphoton Ionization Spectroscopy of Surface Molecules.- Experimental Investigation of the Possibilities of the Optical Tunnelling of Electron from a Metal Surface Induced by Strong CO2 Laser Pulses.- Index of Contributors.