Most of the progress made in particle physics during the last two decades has to led to the formulation of the so called “Standard Model” of elementary particles and its quantitative experimental test. The book deals with this progress but includes chapters which provide the necessary background material to modern particle physics.Particle physics forms an essential part of physics curriculum. This is a textbook but will also be useful for people working in this field and for nuclear physicists, particularly those who work on topics concerning interface between nuclear and particle physics. The book is designed for a semester course for senior undergraduates and a semester course for graduate students. Formal quantum field theory is not used; a knowledge of non-relativistic quantum mechanics is required for some parts of the book; but for the remaining parts the familiarity with the Dirac equation is essential. However, some of these topics are included in the appendix.