This book aims to provide the basis of theoretical foundation and phenomenological knowledge of the structure of matter at the subatomic level. It starts by presenting the general concepts at the simplest level and does not require previous knowledge of the field, except for the basic quantum mechanics. The readers are gradually introduced to the increasingly more advanced topics, so that this text can accompany students all the way to their graduate and doctoral studies in experimental high-energy physics. Special emphasis is placed on experimental and phenomenological aspects of the field and how measurements and theory interplay in the development of particle physics. The book is based on the authors’ undergraduate and graduate lecture c...