The book aims at giving a survey of the most important results of nuclear structure research: basic experimental facts and their interpretation in the framework of shell, geometrical collective and interacting boson (fermion) models. The book is intended first of all for experimental nuclear physicists, doctorands, advanced undergraduate and graduate students, who want to get acquainted with low-energy nuclear structure physics. It is assumed that the reader is familiar with the materials of introductory courses on nuclear physics and quantum mechanics. Otherwise the book aspires to be self-contained, the most important auxiliary scope of knowledge is treated in the appendices. The rigorous mathematical derivations are usually avoided, but the reader will always find references where they can be found. The treatment starts usually from a review of basic experimental facts, then outlines the starting assumptions and main steps of derivations in the framework of the given nuclear structure model. The theoretical results are compared with experimental data, and finally conclusions are drawn: which phenomena could be understood and which problems remained to be solved in the future. The book concentrates on the description of basic experimental and theoretical results, which are proved in many experiments.