Few Particle Problems in the Nuclear Interaction emerged from the International Conference on Few Particle Problems in the Nuclear Interaction held in Los Angeles, from August 28-September 1, 1972. The aim of the conference was to discuss recent developments in low and medium energy few-particle problems. This included the fields of the nuclear three-body problem; nuclear forces (in particular, three-body forces); symmetries; and the interaction of mesons, leptons, and photons with few-nucleon systems. Special sessions were also devoted to the application of the results and techniques of the few-particle research to the problems of other fields, in particular nuclear structure and astrophysics. The conference was organized into nine plenary sessions and 13 parallel sessions. This volume contains 184 papers presented during the nine sessions on the following topics: the nucleon-nucleon interaction; three-body forces; hypernuclear systems; symmetries; three-body problems; multiparticle reactions; proposed studies of few-nucleon systems with meson factories; few-nucleon systems and leptons, mesons, and photons; and applications.

The 1987 Fontevraud Conference gathered more than 100 physicists for the purpose of discussing the latest developments of research on few-body problems. In addition to participants from most European countries representatives from Brazil, Canada, Israel, Japan, South Africa, and the USA took part in the meeting. In the conference program special emphasis was laid on bringing together the various fields, where few-body problems play an important role. Beyond the traditional areas of nuclear and particle physics, in recent years interest has been focussed especially on atomic and molecular physics. This developent is due to the design of new techniques for solving few-body problems under rather general premises. The proceedings contain all plenary talks and the contributions presented orally at the conference. They cover such topics as: few-quark systems and short-range phenomena, two- and three-body forces in quark as well as nucleonic systems, few-hadron bound states, response of few-body systems to electromagnetic and hadronic probes, form factors, hypernuclei, atomic and molecular few-body systems, hyperspherical method, separable expansions, numerical techniques, etc. It appears that recently, even in one year after the Tokyo-Sendai Conference, much progress has been achieved in research on various few-body systems. The present volume gives a comprehensive summary of the modern state of the art and at the same time a proper account of the most recent results obtained in the different institutions and laboratories.

The last decade witnessed an increasing interest of mathematicians in prob lems originated in mathematical physics. As a result of this effort, the scope of traditional mathematical physics changed considerably. New problems es pecially those connected with quantum physics make use of new ideas and methods. Together with classical and functional analysis, methods from dif ferential geometry and Lie algebras, the theory of group representation, and even topology and algebraic geometry became efficient tools of mathematical physics. On the other hand, the problems tackled in mathematical physics helped to formulate new, purely mathematical, theorems. This important development must obviously influence the contemporary mathematical literature, especially the review articles and monographs. A considerable number of books and articles appeared, reflecting to some extend this trend. In our view, however, an adequate language and appropriate methodology has not been developed yet. Nowadays, the current literature includes either mathematical monographs occasionally using physical terms, or books on theoretical physics focused on the mathematical apparatus. We hold the opinion that the traditional mathematical language of lem mas and theorems is not appropriate for the contemporary writing on mathe matical physics. In such literature, in contrast to the standard approaches of theoretical physics, the mathematical ideology must be utmost emphasized and the reference to physical ideas must be supported by appropriate mathe matical statements. Of special importance are the results and methods that have been developed in this way for the first time.

Nuclear physics is undoubtedly a many-body problem. A nice introduction into the present status of this subject may be found in the comprehensive mono graph by P. Ring and P. Schuck "The Nuclear Many-Body Problem" (Springer, Berlin, Heidelberg, New York 1980). However, in view of the many challenging problems that remain to be tackled, it is sensible to consider systems with few particles as model cases. These provide the basis for solving the sophisticated many-body problem posed by intermediate and heavy nuclei. Out of the large number of existing nuclear systems, few-particle, that is few-nucleon, systems can be singled out to form a special group. This is possi ble because a comparatively small number of degrees of freedom (or dynamic variables) is required for a complete description of such systems. In these Lectures we utilize this to study few-body systems in great detail, in particular three-and four-body systems. In contrast to published monographs on the subject, we deal not just with nucleonic degrees of freedom but consider also non-nucleonic degrees of freedom. The range of approaches and methods examined exceeds the scope of other textbooks. The Lectures are organized in such a way as to guide the uninitiated reader through the essentials of solving the dynamical equations of few-body systems directly towards practical applications. Formally oriented readers might like to supplement their reading with texts such as "The Quantum Mechanical Few Body Problem" by W. GlOckle (Springer, Berlin, Heidelberg, New York 1983).

As EPA standards for water quality have tightened in recent years, the need to more accurately assess filter performance and improve the overall treatment process has led to increased demand for the high sensitivity provided by particle counters. One particle counter can give you more data than a dozen turbidimeters-if you know how to sort through