This book aims to succinctly describe our current theoretical understanding of the nuclear many-body problem. The vast material accumulated over recent decades can be categorized into two main approaches: focusing on physical phenomena like single-particle excitations, rotations, and vibrations, or emphasizing the methodologies and technical aspects of various theories. This work adopts the latter approach, organizing content by the different methods employed—such as Hartree-Fock theory, time-dependent Hartree-Fock theory, generator coordinates, and boson expansions—rather than by physical subjects. While many theories have been covered in other textbooks, this book seeks to provide a more comprehensive perspective. It includes brief reviews of established topics, like the liquid drop and shell models, and offers updated discussions on areas such as rotations and the random phase approximation. The primary goal is to present modern theories—like boson expansions, generator coordinates, time-dependent Hartree-Fock, and semiclassical theories—that have either not been extensively covered or have not appeared in book form before.
