An Institute like ours cannot help but lend credence to the notion of the late Derek J. de Solla Price of Yale University that "the scientific revolution was largely the improvement, invention and use of a series of instruments . . . . that expanded the reach of science in innumerable directions". Most of science today and in years gone by depends on the experimental observation of struc ture on the small scale with microscopes, and on the large scale with telescopes. The first instruments to expand the observational range of the human eye were simple optical systems, designed in the case of microscopes and telescopes to magnify the image. The big breakthrough in the 17th century was not when Galileo first turned his telescope to the heavens, but when improvements in lens-grinding techniques allowed eyeglass makers to make the first telescope. Early microscopy revealed new and previously unsuspected microstruc tures in biological and non-biological materials and thus helped to enlarge on the understanding of the relationship between structure and properties. The natural inclination of all microscopists, the desire to observe ever smaller structures, was satisfied by the construction of higher quality optical systems which reduced the aberrations limiting the usable magnification. The modem optical microscope is the result of this evolution in design and construction, and it can be operated easily to achieve close to the theoretical resolution.

The sixth Ettore Majorana International School of Mathematical Physics was held at the Centro della Cultura Scientifica Erice, Sicily, 1-14 July 1985. The present volume collects lecture notes on the ses sion which was devoted to Fundamental Problems of Gauge Field Theory. The School was a NATO Advanced Study Institute sponsored by the Italian Ministry of Public Education, the Italian Ministry of Scientific and Technological Research and the Regional Sicilian Government. As a result of the experimental and theoretical developments of the last two decades, gauge field theory, in one form or another, now pro vides the standard language for the description of Nature; QCD and the standard model of the electroweak interactions illustrate this point. It is a basic task of mathematical physics to provide a solid foundation for these developments by putting the theory in a physically transparent and mathematically rigorous form. The lectures and seminars of the school concentrated on the many unsolved problems which arise here, and on the general ideas and methods which have been proposed for their solution. In particular, we mention the use of rigorous renormalization group methods to obtain control over the continuum limit of lattice gauge field theories, the explora tion of the extraordinary enigmatic connections between Kac-Moody Virasoro algebras and string theory, and the systematic use of the theory of local algebras and indefinite metric spaces to classify the charged C* states in gauge field theories.

Treatise on Materials Science and Technology, Volume 27: Analytical Techniques for Thin Films covers a set of analytical techniques developed for thin films and interfaces, all based on scattering and excitation phenomena and theories. The book discusses photon beam and X-ray techniques; electron beam techniques; and ion beam techniques. Materials scientists, materials engineers, chemical engineers, and physicists will find the book invaluable.

The possibility of direct interfacing between biological and technological information devices could result in a merger of mind and machine - Ultimate Computing. This book, a thorough consideration of this idea, involves a number of disciplines, including biochemistry, cognitive science, computer science, engineering, mathematics, microbiology, molecular biology, pharmacology, philosophy, physics, physiology, and psychology.

The Ninth Course of the International School of Cosmology and Gravita tion of the Ettore Majorana Centre for Scientific Culture is concerned with "Topological Properties and Global Structure of Space-Time." We consider this topic to possess great importance. Our choice has also been influenced by the fact that there are many quest ions as yet unre solved. Standard general relativity describes space-time as a four-dimensional pseudo-Riemannian manifold, but it does not prescribe its large-scale structure. Inorderto attempt answers to some topological questions, such as whether our universe is open or closed, whether it is orientable, and whether it is complete or possesses singularities, various theoretical approaches to global aspects of gravitational physics are presented here. As topological questions playa role in non-standard theories as weIl, it will be found that some of the lectures and seminar talks in this volume adopt the point of view of standard relativity, whereas others are based on different theories, such as Kaluza-Klein theories, bimetric theories, and supergravity. We have found it difficult to organize these papers into classes, say standard and non-standard theory, or models with and without singularities. One paper, by R. Reasenberg, is experimental. Its purpose was to give the theorists present an inkling of the opportunities, as weIl as the pitfalls, of experimental research in gravitational physics. Accordingly, we have arranged all contributions alphabetically, by ~first-named) author.