Presenting a comprehensive account of the physical concepts and theoretical approaches developed for the study of the dynamical properties of liquids (or, more generally, of high-density fluids), at a microscopic level, this book first discusses the basic dynamical phenomena to be interpreted, as well as the various experimental probes. It then proceeds to an exposition of the sophisticated theoretical techniques needed for a satisfactory account of both single particle and collective motions. The complications are faced in a stepwise fashion, with special attention to the physical content of the results. Based on the results of the progress achieved in the last decade the book provides a satisfactory understanding of most of the phenomena characterising this fascinating field.

An international workshop on Elementary Excitations and Fluctuations in Magnetic Systems was held in Turin for five days beginning 25 May, 1987. The workshop followed much the same format as the one with the same title held in San Miniato in 1984 (proceedings: Springer Series in-Solid-State Sciences, Vol. 54), that most participants contributed talks and provided papers for the proceedings. While many of the participants had attended the first workshop, 15 of the 40 invited review papers were presented by scientists who had not. The majority of the talks reported theoretical work concerned with the introduction of new techniques. However, experimental work was also well represented, not least because many of the reported theoretical studies were motivated by experimental findings, and a highlight of the workshop was an extremely stimulating session devoted to recent neutron scattering measure- ments, on various systems, that exploited polarization analysis. The fine venue of the workshop, Villa Gualino, with its excellent facili- ties and spacious accommodation, helped to produce a delightful relaxed and friendly atmosphere. For the use of Villa Gualino and significant financial support we are indebted to our host organization, the Institute for Scien- tific Interchange (lSI). Additional financial support came from the Consiglio Nazionale delle Ricerche (CNR), Centro Interuniversitario di Struttura della Material del Ministero della Pubblica Istruzione (CISM-MPI) and Gruppo Nazionale di Struttura della Materia (GNSM-CNR).