I have written this book with many practical and contemporary examples keeping in mind the students' perspectives and their subject problems. There are many excellent books published in the past on this subject, with the help of which I have been able to write this book, which has been mentioned under the reference. I hope that this book will prove to be very beneficial for the students of education. I have received direct and indirect support of many people in bringing this book in tangible form, I express my heartfelt gratitude to all those people. Especially Sudivya Prakashan, who helped me in publishing this book to the students. I take utmost care in writing this book, yet human error is possible. Your suggestions regarding this book will always be welcome.