Mathematics is a beautiful and interesting branch of study of study. However, many students unnecessarily have a phobia about it. My effort in this has been to present the theory, examples and questions in a coherent and well-knit manner, not only encourage the students to learn and understand the subject but also provide an insight into is beauty. The book entitled Understanding ISC Mathematics is a textbook brought out in two volumes – Vol I and Vol II prepared for the students of class XII. This book covers the complete contents of the latest syllabus prepared and prescribed by the ISC Board to be implemented from the current academic session. The book has been prepared as per the New Education Policy (NEP). The book adheres to the latest curriculum and syllabus prescribed by the Council for the Indian School Certificate Examinations, New Delhi (CISCE). Also, NCERT book and Exemplar problems have been consulted. A new feature, ‘Illustrative Examples for Multiple Choice Questions’ followed by ‘Multiple Choice Questions’, Statement I/II Type Questions, Assertion-Reason and Competency Focused Questions have been added. However, the students are advised not to read this book like a storybook-they should sit with a pencil and notepad, and whenever during theory or examples, we say, please do it !, it is necessary that the students do those steps. The entire matter is given in a logical sequence so as to develop and strengthen the concepts. Ultimately conceptual clarity is what is needed for success in any examination-be it ISC or IIT JEE or any other competitive examination.