Amazon.com description: Product Description: This text describes the gravitational interactions and evolution of astronomical systems on all scales, from small groups of stars through galaxies and clusters of galaxies to the Universe itself. In a rapidly developing area of astronomy, it is the first comprehensive treatise on the subject to be published since the early 1960s. Concentrating on the basic physics, at a graduate student level, it also develops many astronomical applications in considerable detail. The book is self-contained. Most results are derived from preceding ones in a straightforward way. It is written to bring out the physical content behind the mathematical formulae, and contains a number of exercises and suggestions for research topics. Bibliographies with nearly 300 selected references provide gateways into the literature.