This is for students of GNM. This is designed as per the student's perspective to provide the knowledge of better understanding and easy accessibility. The complexities of topics have been avoided. Explanations are there in detail and accompanied with diagrams, flow charts, tables, and examples wherever required. Important points are highlighted wherever required. Students seeking an easy explanation of concepts with less complexities would definitely enjoy this book's learning journey. This book will be a helping guide for students who’ll pursue it for studies.