It gives us immense pleasure to present the revised Edition of the book. This edition has further improved with the suggestions made by the readers and incorporated completely with Java as a programming language as per the new syllabus prescribed by the Council. Before beginning with the basic principles of Object-Oriented Programming (OOP), a deductive approach has been introduced for an easy understanding of OOP language. Especially, the elementary concept of Object and Classes are well explained with real life examples. The theories have been reframed along with various illustrations and examples. Exercises of the chapters are well upgraded with objective as well as subjective questions. The solved programs (decision making and iterations based) have been designed to develop the self-confidence among the students. Further, practicing these programs will enable the students to build their confidence while working with the exercises. Moreover, this book has been prepared keeping in view that it will be helpful in Class X as well as for the Council examination.