A book explaining magnetism.We now come to another book in the Science for Everyone series called Nature of Magnetism. The authors of the book M. I. Kaganov and V. M. Tsukernik say in the opening chapter of the book What is the subject of this book?The title of the book represents fairly well the subject this book. We shall attempt to explain the Nature of Magnetism. One of the large branches of physics is the physics of electromagnetic phenomena. By the beginning of the 20th century it has seemed that the work of Faraday and Maxwell successfully completed this field of science: completed it in the sense that the main laws governing the behavior of electromagnetic fields were understood, that is, the necessary equations were written, and the task of subsequent generations of physicists was to search for more and more exotic solutions of these equations. But gradually it became clear that research in the field was far from complete. Owing to the injection of quantum ideas, the theory of electromagnetic phenomena has undergone essential changes, no less serious than those in mechanics. Nowadays we are much more careful in evaluating whether a part of physics has been completed or not. Any sufficiently developed science formulates not only its fundamental principles but also the boundaries beyond which these principles are not valid. Unless we go into the atomic structures, quantum mechanics and the theory of electromagnetism, that are basic for our understanding of the structure and properties of the surrounding world, can be successfully applied to study an enormously broad field of phenomena. There is no reason to doubt the validity of the laws at present: we are within the limits of their application.And they continueReaders are often scared away by mathematical complexities. We did take this factor into account but could not avoid using vectors and operations with them, the notions of function, and of its derivative and integral; however, we never go beyond this level. Some  mathematical operations are intentionally shifted to Problems. A reader who solves the problems will understand the book much more profoundly than one who puts off solving them for some time in the future. But what worries us most about the reader's response does not concern mathematical difficulties. We expect that the main obstacle for the reader will be many new physical concepts.And it is so, if you are put off by glimpse of a mathematical equation, then the best way is to confront it, otherwise it will be always so. The back cover of the book says:This popular science physics book, dealing with precisely what the title suggests, exposes the reader to a fascinating interplay of classical, statistical, and quantum approaches to matter.The book describes microscopic sources of magnetic field and explains why not all macroscopic bodies  produce magnetic fields. The question why different bodies behave differently in a response to applied magnetic field is considered, and ferro-magnetism and  anti-ferro-magnetism are explained in detail. The study of magnetic structures and other interesting problems are also discussed.The book was translated from the Russian by V. I. Kisin and was first published by Mir in 1985. I had a hard copy of the book, which I lost after I gave it to someone, the person never returned it (was it purposeful or not I do not know). This electronic copy is a sort of consolation now, thanks Anish.Dot for this book.The book has following chapters and sections:Introduction. What is the subject of this book? 7Chapter 1 Elementary Magnets1.1 Electric and Magnetic Dipoles 191.2 Gyromagnetic Ratio 251.3 Elementary Sources of Magnetic Field Do They Exist? Ampere's Hypothesis 271.4 A Brief Overview: of Quantum Mechanics 33Uncertainty Relations, Particle-Waves 34Stationary States 38More on Hydrogen Atom  421.5 Angular Momentum. Space Quantization 451.6 Magnetic Moment in Magnetic Field 501.7 Spin and Intrinsic Magnetic Moment of the Electron 541.8 g Factor 611.9 Structure of Atoms 68Pauli Exclusion Principle  771.10 Exchange Energy 84Chapter 2. Paramagnetism and Diamagnetism2.1 Magnetic Susceptibility 922.2 Magnetic Field Aligns Magnetic Moments 98Negative Absolute Temperatures 103Electron Paramagnetic Resonance 1092.3 Diamagnetism 111Magnetism Is a Quantum Phenomenon 1182.4 Metals. Pauli Paramagnetism 121Fermi and Bose Gases 1232.5 Metals. Landau Diamagnetism 1312.6 Superconductors: Ideal Diamagnetics 136Chapter 3. Ferromagnetism 3.1 Self-ordering of Atomic Magnets 1423.2 Ferromagnetism as a Result of Exchange Forces 153Ferromagnetic Metals 1593.3 The "Para-Ferro" Transition: One ofthe Second-Order Phase Transitions 1603.4 What Is the Direction of the Magnetic Moment of Ferromagnotics? Energy of Magnetic Anisotropy 1683.5 Domains 1773.6 Technical Magnetization Curve 1863.7 Spin Waves 194Spin Complexes 2083.8 Spin Waves as Waves of Nonuniforrn Precession 2133.9 Gas of Magnons 217Bose Gas 218Quantum Oscillator 2233.10 Magnetization and Heat Capacity Ferromagnetics at Low Temperatures 228Phonons 232Chapter 4. Antiferrornagnetism4.1 Antiferromagnetic Ordering 2404.2 Magnetic Field Changes the Structure of Antiferromagnetics4.3 Spin Waves: Magnons in Anti-ferromagnetics 2564.4 How to "See" an magnon? 265Ferromagnetic Resonance 267Ferroacoustic Resonance 273Inelastic Scattering  274Problems 279