Primarily intended for the first-year undergraduate students of all branches of engineering, this textbook provides a sound understanding of the fundamental concepts and principles of physics in a simple and easy-to-understand style. This textbook is organized in ten chapters covering the modules of the syllabus corresponding to interference of light, diffraction, polarization, optical instruments, laser, fibre optics, mechanics and special theory of relativity. Apart from giving a detailed theoretical analysis of the topics, various pedagogical aids such as solved numerical problems and Review Questions are also included at the end of each chapter. An effort has been made to ensure that all the topics taught in a single semester are presented within a single volume. The book is written in accordance with the syllabi prescribed by the Guru Gobind Singh Indraprastha University and University of Delhi, but the topics covered in this book are also prescribed in the syllabi of almost all the universities and institutes. Therefore, the text will be useful for all the first-year engineering students studying in Indian Universities as well as Foreign Universities.