While studying the Hetero-cyclic compounds, only collection of reactions and examples create confusion in readers mind. This book is written with the purpose to learn the representative hetero-cyclic compounds so that further it can be extrapolated by the reader to learn new hetero-cyclic compound. To suffice the purpose, every molecule is discussed in detail starting from its history to present research work. Most of the reactions are discussed with mechanism in detail. Also wherever possible, examples are included. A list of references is mentioned at the end of each chapter which is useful for researchers also.