Calculus is the first subject that broke the conventional rules of mathematics and It was the first achievement of modern mathematics. This is one of the powerful tools found by Sir Isaac Newton which is used in so many applications. But the way to understand the formation of calculus is not yet taught clearly in school and colleges. Even-though our school curriculum gives much importance to calculus, still, students find so much difficulty to understand it. Other mathematics concepts can be easily correlated with day to day applications. But the application of calculus can be easily visualized only by scientists, economists and engineers.The book deals with the concept of the heart of engineering mathematics known as "Calculus." Fundamental concepts of Calculus with its physical and geometrical meanings are explained in simple wording. Those who are having basic fundamental knowledge in mathematics can easily understand this book. The book is divided into five categories. The first part is the chapter that bridges school fundamentals to the introduction of calculus. In the second part, the concepts of Differentiation is explained from the basics of school mathematics. Then the application of Differentiation is explained. The fourth part introduces the concept of integration and explains the meaning of Integration and methods of doing integration. The final part is the explanation of the creation of a new topic called "Differential Equations." And this book is not like the traditional Calculus textbook. It gives a brief explanation only to concepts not much focused on academic problems. It gives a clear explanation for the background of mathematics theorem and problems.