This text offers a brief introduction to the dispersion relations as an approach to calculate S-matrix elements, a formalism that allows one to take advantage of the analytical structure of scattering amplitudes following the basic principles of unitarity and causality. First, the case of two-body scattering is considered and then its contribution to other processes through final-state interactions is discussed. For two-body scattering amplitudes, the general expression for a partial-wave amplitude is derived in the approximation where the crossed channel dynamics is neglected. This is taken as the starting point for many interesting nonperturbative applications, both in the light and heavy quark sector. Subsequently crossed channel dynamics is introduced within the equations for calculating the partial-wave amplitudes. Some applications based on methods that treat crossed-channel dynamics perturbatively are discussed too. The last part of this introductory treatment is dedicated to the further impact of scattering amplitudes on a variety of processes through final-state interactions. Several possible approaches are discussed such as the Muskhelishvili-Omnes dispersive integral equations and other closed formulae. These different formalisms are then applied in particular to the study of resonances presenting a number of challenging properties. The book ends with a chapter illustrating the use of dispersion relations in the nuclear medium for the evaluation of the energy density in nuclear matter.

Our understanding of galaxies, the building blocks of the Universe has advanced significantly in recent years. New observations from ground- and space-based telescopes, the discovery of dark matter, and new insights into its distribution have been instrumental in this. This textbook provides graduate students with a modern introduction to the gravitationally determined structure and evolution of galaxies. Readers will also benefit from detailed discussions of the issues involved in the process of modeling complex stellar systems. Additionally, the text provides an accessible framework for interpreting observations and devising new observational tests. Based on the author's extensive teaching experience, this second edition features an up-to-date view of basic phenomenology, a discussion of the structure of dark halos in galaxies, the dynamics of quasi-relaxed stellar systems and globular clusters, galaxies and gravitational lensing and an introduction to self-gravitating accretion disks. Extended problem sets are available from the accompanying resources website: www.cambridge.org/9781107000544.

Mechanics of Continua and Wave Dynamics is a textbook for a course on the mechanics of solids and fluids with the emphasis on wave theory. The material is presented with simplicity and clarity but also with mathematical rigor. Many wave phenomena, especially those of geophysical nature (different types of waves in the ocean, seismic waves in the earth crust, wave propagation in the atmosphere, etc.), are considered. Each subject is introduced with simple physical concepts using numerical examples and models. The treatment then goes into depth and complicated aspects are illustrated by appropriate generalizations. Numerous exercises with solutions will help students to comprehend and assimilate the ideas.