Textbook in PDF format This book will develop a conceptual background to understand the basis of quantum electrodynamics (QED) with a minimal mathematical background. However, it will not only give an idea of required mathematical background but assist to understand the basic mathematical techniques. It will also provide some frequently used mathematical relations all at one place and use them whenever needed. In this way, it will prepare beginners to learn QED and even help advanced level students in the field to fill up the conceptual gaps