This volume contains most of the papers presented at the "Workshop on Quasielastic Light Scattering Studies of Fluids and Macromolecular Solutions" held at CISE, Segrate (Milano), Italy, from 11 to 13 May, 1979. Quasielastic light scattering (also called self-beating spectroscopy or intensity correlation spectroscopy) is the technique, introduced by Benedek and coworkers and by Cummins and coworkers about 15 years ago, by which dynamical information about a scattering medium is obtained through the measurement of the power spectrum (or the intensity correlation function) of the laser light scattered from the medium. The technique received in the early seventies a considerable impulse from the development of real-time fast digital correlators. The aim of the Workshop was to bring together a selected number of researchers in order to discuss recent developments in quasielastic light scattering and related optical methods and to report about new applications of the technique in physics, chemistry and biology. The first two days of the meeting were devoted to the oral presentations of papers. In the third day an informal session was held which included a very lively and thorough discussion of the highlights of the Workshop. Most part of the technical problems were debated during the informal session and during the subsequent visits to the light scattering laboratory in CISE.