This book is a compilation of chapters that discuss the most vital concepts in the field of modern quantum mechanics. It is designed to provide students with the basic concepts and applications of this field. Modern quantum mechanics refers to the study of processes of photons and atoms. It is based on quantum field theory. This text attempts to understand the multiple branches that fall under the discipline of modern quantum mechanics and how such concepts have practical applications. Such selected concepts that redefine the field of modern quantum mechanics have been presented in this book. It studies, analyses and upholds the pillars of the subject and its utmost significance in modern times. This textbook attempts to assist those with a goal of delving into this field.