An open textbook that is suitable for the first semester of Organic Chemistry. Basic concepts of the structures and reactivities of organic molecules are covered in this open textbook. Besides the fundamental discussions of organic acids-bases, stereochemistry, IR and NMR, this book also includes the topics of substitution and elimination reactions, radical substitution of alkanes, preparation and reactions of alkenes and alkynes. Front Matter 1: Basic Concepts in Chemical Bonding and Organic Molecules 2: Fundamental of Organic Structures 3: Acids and Bases- Organic Reaction Mechanism Introduction 4: Conformations of Alkanes and Cycloalkanes 5: Stereochemistry 6: Structural Identification of Organic Compounds- IR and NMR Spectroscopy 7: Nucleophilic Substitution Reactions 8: Elimination Reactions 9: Free Radical Substitution Reaction of Alkanes 10: Alkenes and Alkynes Back Matter