From the reviews: "Cini has prepared an advanced book in a specialized area of quantum physics ... . The author has divided the book into five broad topics: many-body physics, symmetry in quantum physics, Green's function techniques, nonperturbative applications, and exact results in many-body problems. ... There are problems at the end of each chapter with solutions. ... There are some diagrams to explicate the text and a good index. ... Graduate students through professionals." (N. Sadanand, CHOICE, Vol. 45 (7), 2008) "This text is aimed at students specialising in condensed matter theory and is structured as an introductory course to the topic. ... this text discusses some exact results that can be obtained pertaining to quantum phases and repulsive interactions. Ultimately this book provides an interesting introduction to an area of active research." (M. Foreman, Contemporary Physics, Vol. 50 (2), March-April, 2009) "This book treats various theoretical topics in condensed matter physics ... . This book is aimed mainly at condensed matter physicists who are working in the area of atomic and solid state physics, and who are looking for some systematic methods and numerical algorithms. It can also be of interest for undergraduate students ... in quantum physics, operational computation and algebra." (Jean-Yves Fortin, Mathematical Reviews, Issue 2009 c) "The present book is devoted to condensed matter physics, which includes theoretical background of the theory and their use in applications, i.e. in experiments. ... the book is well written, readable and the mathematical treatments are explained in enough detail. Proofs of all the relevant theorems are given. There are a lot of illustrative examples, and relevant problems. ... the book provides material for courses in theoretical physics, and it is recommended for undergraduate and graduate students specializing in condensed matter physics." (Farruh Mukhamedov, Zentralblatt MATH, Vol. 1146, 2008)