Two topics in the forefront of superconductor research--superconductor-insulator transition in thin films and vortex tunneling in granular, bulk, and high temperature superconductors--have never before been given a unified and deductive treatment. This monograph and text provides a much-needed, comprehensive introduction to the theory of quantum fluctuations in inhomogenous superconducting materials. It be will be of great use to students and researchers in disciplines such as superconductivity, many-body systems, phase transitions, submicron physics, and surface science.

The workshop entitled Magnetic Susceptibility of Superconductors and other Spin Systems (S4) was held at Coolfont Resort and Health Spa. located near Berkley Springs West Virginia on May 20-23. 1991. There were over sixty attendees. approximately half from the United States. the remainder representing over twelve different countries. The international character of the workshop may be gleaned form the attendee list, included in this volume. The intent of the workshop was to bring together those experimentalists and theoreticians whose efforts have resulted in significant recent contributions to the development and use of the ac susceptibility technique as well as to the interpretation of data obtained from these measurements. Many spirited discussions occurred during and after the presentations. These are reflected in the manuscripts contained in these proceedings. Although camera ready manuscripts were required from all participants at registration, all manuscripts were revised and reflect the lively exchanges that followed each presentation. The small size of the workshop allowed the participants a high degree of flexibility. Consequently when a controversial topic such as "the irreversibility line" emerged, a special session was organized on the spot. At the suggestion of Ron Goldfarb, participants were invited to contribute a one page summary containing their thoughts on the topic. These stand alone contributions were retyped and included as submitted, with only minor editorial changes. These proceedings are intended for those experienced scientists new to the field and graduate students just beginning their research.

Infrared and Millimeter Waves, Volume 13: Millimeter Components and Techniques, Part IV compiles the work of several authors while focusing on certain aspects of infrared and millimeter waves, such as sources of radiation, instrumentation, and millimeter systems. This volume covers millimeter components and techniques. This text first covers the use of powerful gyrotrons for thermonuclear research, and then discusses high-power coherent radiation sources. Kinetic theory of harmonic gyrotron oscillator with slotted resonant structure is the focus of Chapter 3, while integrated fin-line components for communication, radar, and radiometer applications is the subject of Chapter 4. The fifth chapter discusses propagation and mode coupling in corrugated and smooth-wall circular waveguides. Chapter 6 discusses far-infrared properties of inhomogeneous materials, and the last chapter covers solid-state spectroscopy with far-infrared continuous-wave lasers. This book will be of great use to researchers or professionals whose work involves infrared and millimeter waves.

Since the discovery of superconductivity in 1911 by H. Kamerlingh Onnes, of the order of half a billion dollars has been spent on research directed toward understanding and utiliz ing this phenomenon. This investment has gained us fundamental understanding in the form of a microscopic theory of superconduc tivity. Moreover, superconductivity has been transformed from a laboratory curiosity to the basis of some of the most sensitive and accurate measuring devices known, a whole host of other elec tronic devices, a soon-to-be new international standard for the volt, a prototype generation of superconducting motors and gener ators, and magnets producing the highest continuous magnetic fields yet produced by man. The promise of more efficient means of power transmission and mass transportation, a new generation of superconducting motors and generators, and computers and other electronic devices with superconducting circuit elements is all too clear. The realization of controlled thermonuclear fusion is perhaps totally dependent upon the creation of enormous magnetic fields over large volumes by some future generation of supercon ducting magnets. Nevertheless, whether or not the technological promise of superconductivity comes to full flower depends as much, and perhaps more, upon economic and political factors as it does upon new technological and scientific breakthroughs. The basic science of superconductivity and its technological implications were the subject of a short course on "The Science and Technology of Superconductivity" held at Georgetown University, Washington, D. C. , during 13-26 August 1971.