In recent years substantial progress has been made in the detection of surface phonons owing to considerable improvements in inelastic rare gas scattering tech niques and electron energy loss spectroscopy. With these methods it has become possible to measure surface vibrations in a wide energy range for all wave vectors in the two-dimensional Brillouin zone and thus to deduce the complete surface phonon dispersion curves. Inelastic atomic beam scattering and electron energy loss spectroscopy have started to play a role in the study of surface phonons similar to the one played by inelastic neutron scattering in the investigation of bulk phonons in the last thirty years. Detailed comparison between experimen tal results and theoretical studies of inelastic surface scattering and of surface phonons has now become feasible. It is therefore possible to test and to improve the details of interaction models which have been worked out theoretically in the last few decades. At this point we felt that a concise, coherent and self-contained guide to the rapidly growing field of surface phonons was needed."

The future of information technology requires ultra-high speed processing and large data storage capacity. Since the electronics technology using semi-cond- tors and inorganic materials is about to reach its limits, much current research is focused on utilizing much faster photons than electrons, namely photonics. To achieve any significant effect on the actual use of the science of photonics, dev- opments of more efficient photonics materials, better optical property evaluations, manufacture of devices for system applications, etc. are the subjects which need to be explored. In particular, the development of photonics materials stands in the forefront of research as this constitutes the most pertinent factor with regard to the development of ultra-high speed and large capacity information processing. In this respect, there has been continuous research on photo-responsive materials through molecular structure design and architecture and the results so far are very promising as functions and performances are beginning to realize their high expectations. The two special volumes "Polymers for Photonics Applications"give authori- tive and critical reviews on up-to-date activities in various fields of photonic po- mers including their promising applications. Seven articles have been contributed by internationally recognized and they deal with, polymers for second- and thi- order nonlinear optics, quadratic parametric interactions in polymer waveguides, electroluminescent polymers as light sources, photoreflective polymers for ho- graphic information storage, and highly efficient two-photon absorbing organics and polymers.

The two special volumes of Advances in Polymer Science entitled "Polymers for Photonics Applications" provide authoritative and critical reviews of up-to-date research and advances in various fields of photonic polymers as well as their promising applications. Eight articles contributed by internationally recognized scientists are concerned with polymers for second- and third-order nonlinear optics, quadratic parametric interactions in polymer waveguides, electroluminescent polymers for light sources, photoreflective polymers for holographic information storage, and highly efficient two-photon absorbing organics and polymers, including their applications. This review should provide individuals working in the field of photonic polymers with invaluable scientific knowledge on the state of the art while giving directions for future research to those deeply interested.