The present book targets particle physics students, but it would also be useful for general postgraduate students in physics. Students preparing for various competitive examinations, particularly related to higher education including research, will also find that the contents meets their requirements. Most of the topics present in the model syllabus of University Grants Commission for Post Graduate Particle Physics (III Semester), Nuclear and Particle Physics (IV Semester, Strong, Weak and Electromagnetic Interactions) and Quantum Electrodynamics have been covered in the book. The topics have been developed in a pedagogical manner by providing all possible algebraic details. Assignments are given at the end of each chapter. The assignments contain descriptive questions, as well as problems. Most of the questions are based on the material of the chapter itself. A new feature of the book is the substantial number of objective-type questions that follow the assignments of each chapter to help prepare the students for GATE, NET and related examinations.