Recent advances in experimental techniques now enable researchers to produce in a laboratory clusters of atoms of desired composition from any of the elements of the periodic table. This has created a new area of research into novel materials since clusters cannot be regarded either as a "large" molecule or as a fragment of the bulk. Both experimental and theoretical studies are revealing unusual properties that are not ob served in solid state environments. The structures of micro-clusters are found to be significantly distorted from the most symmetric arrangement, some even exhibiting pentagonal symmetry commonly found in icosahedric structures. The unusual stability of certain clusters, now described as "magic number species", shows striking similarities with the nuclear shell structure. The relative stabilities of clusters depend not only on the composition of the clusters but also on their charged states. The studies on spontaneous fragmentation of mUltiply charged clusters, commonly referred to as Coulomb explosion, illustrate the role of electronic bonding mechanisms on stability of clusters. The effect of foreign atoms on geometry and stability of clusters and the interaction of gas atoms with clusters are showing promise for an indepth understanding of chemisorption and catalysis. The magnetic and optical properties are dependent not only on cluster size but also on its geometry. These findings have the potential for aiding industry in the area of micro-electronics and catalysis.

On Friday, February 20, 1980, I had the pleasure to be present at the inaugural lecture of my colleague Jan Reedijk, who had just been named at the Chair of Inorganic Chemistry of Leiden University. According to tradition, the ceremony took place in the impressive Hall of the old University Academy Building. In the course of his lecture, Jan mentioned a number of recent developments in chemistry which had struck him as particularly important or interesting. Among those was the synthesis of large metal cluster compounds, and, to my luck, he showed a slide ofthe molecular structure of [PtI9(C)b]4-. (To my luck, since at traditional Leiden University it is quite unusual to show slides at such ceremonies.) This constituted my first acquaintance with this exciting new class of materials. I became immediately fascinated by this molecule, partly because of the esthetic beauty of its fivefold symmetry, partly because as a physicist it struck me that it could be visualized as an "embryonically small" metal particle, embedded in a shell of CO ligands.

Recent innovations in experimental techniques such as molecular and cluster beam epitaxy, supersonic jet expansion, matrix isolation and chemical synthesis are increasingly enabling researchers to produce materials by design and with atomic dimension. These materials constrained by sire, shape, and symmetry range from clusters containing as few as two atoms to nanoscale materials consisting of thousands of atoms. They possess unique structuraI, electronic, magnetic and optical properties that depend strongly on their size and geometry. The availability of these materials raises many fundamental questions as weIl as technological possibilities. From the academic viewpoint, the most pertinent question concerns the evolution of the atomic and electronic structure of the system as it grows from micro clusters to crystals. At what stage, for example, does the cluster look as if it is a fragment of the corresponding crystal. How do electrons forming bonds in micro-clusters transform to bands in solids? How do the size dependent properties change from discrete quantum conditions, as in clusters, to boundary constrained bulk conditions, as in nanoscale materials, to bulk conditions insensitive to boundaries? How do the criteria of classification have to be changed as one goes from one size domain to another? Potential for high technological applications also seem to be endless. Clusters of otherwise non-magnetic materials exhibit magnetic behavior when constrained by size, shape, and dimension. NanoscaIe metal particles exhibit non-linear opticaI properties and increased mechanical strength. SimiIarly, materials made from nanoscale ceramic particIes possess plastic behavior.

These issues represent a compendium of review papers covering almost every aspect of the physics of clusters and nanophase materials. Papers have been written by leading international experts in the field. The purpose of this compendium has been to illustrate, in more detail than is possible in a conference paper, the fundamental or underlying principles.

Metal Nanoclusters in Catalysis and Materials Science: The Issue of Size Control deals with the synthesis of metal nanoclusters along all known methodologies. Physical and chemical properties of metal nanoclusters relevant to their applications in chemical processing and materials science are covered thoroughly. Special attention is given to the role of metal nanoclusters size and shape in catalytic processes and catalytic applications relevant to industrial chemical processing.An excellent text for expanding the knowledge on the chemistry and physics of metal nanoclusters. Divided in two parts; Part I deals with general aspects of the matter and Part II has to be considered a useful handbook dealing with the production of metal nanoclusters, especially from their size-control point of view.* Divided into two parts for ease of reference: general and operational * Separation of synthetic aspects, physical properties and applications* Specific attention is given to the task of metal nanoclusters size-control

This handbook is a guide to current methods of computational chemistry, explaining their limitations and advantages and providing examples of their applications. The first part outlines methods, the balance of volumes present numerous important applications.

The book contains impressive results obtained in the XX-th century and discussion of next challenges of the XXI-st century in understanding of the nanoworld. The main sections of the book are: (1) Physics of Nanostructures, (2) Chemistry of Nanostructures, (3) Nanotechnology, (4) nanostructure Based Devices. Contents: Physics of Nanostructures: Polarons in Quantum Wells (A I Bibik et al.); Screening of Extra Point Charge in a Few Particle Coulomb System (N A Poklonski et al.); Electric Field Effect on Absorption Spectra of an Ensemble of Close-Packed CdSe Nanocrystals (L I Gurinovich et al.); Influence of Surface Phases on Electrical Conductivity of Silicon Surface (D A Tsukanov et al.); Chemistry of Nanostructures: Formation of Ultradisperse Bimetallic Particles by Redox Processes in Aqueous Solutions (Yu A Fedutik et al.); Fast Electrochemical Impedance Spectroscopy for Nanochemistry and Nanophysics (G A Ragoisha & A S Bondarenko); Features of Luminescent Semiconductor Nanowire Array Formation by Electrodeposition into Porous Alumina (S A Gavrilov et al.); Nanotechnology: Massively Parallel Atomic Lines on Silicon Carbide (P Soukiassian); Advancing Magnetic Force Microscopy (I Fedorov et al.); Porous Silicon as a Material for Enhancement of Electron Field Emission (A A Evtukh et al.); Nanostructure Based Devices: A New Multipeak Resonant Tunneling Diode for Signal Processing Application (A N Kholod et al.); Long Term Charge Relaxation in Silicon Single Electron Transistors (A Savin et al.); Resonant Tunneling Through an Array of Quantum Dots Coupled to Superconductors Under the Effect of Magnetic Field (A N Mina); and other papers. Readership: Undergraduates, PhD students and researchers in nanotechnology.