This book is not a textbook. It is a refresher text to help students revise their lessons in the quickest possible way and in the most effective manner. It does not over emphasize theories, as has been done in several other competitive books available in the market. However, every care has been taken to ensure that no important theory is left out. This book has several new features: coverage of the syllabus of JEE (Main + Advanced); a great number of solved numerical examples to acquaint students with the application of several theories, solution at the end of each exercise and two levels of questions at the end of the chapters to give readers an opportunity to assess their understanding of the chapters. The use of easily understandable language is at the core of the author's efforts.