This book deals with the basic approaches of many branches of chemistry through its interest in the following subjects: quantum theory and atomic structure (chapters from 1 to 5), discovery and periodic classification of chemical elements (chapters from 6 to 9), types and theories of chemical bonding (chapters 10, 11, and 13), isomerism (chapter 12), nomenclature of chemical species (inorganic compounds, chapter 14; organic compounds, chapters 15 and 16; and some natural compounds, chapter 17), chemical equation and types of inorganic and organic reactions (chapter 18), chemical calculation (chapter 19), oxidation-reduction reactions and their applications (chapters 20 and 21), chemical thermodynamics (chapter 22), solutions (chapter 23), chemical and ionic equilibrium (chapters 24, 25, and 26), and chemical kinetics (chapter 27).