This book presents a simple and clear picture of symmetry and its breaking in quantum field theory by discussing the physics of elementary field theory of fermions interacting by gauge fields, as well as by four body fermion fields. In this respect, the interpretation of the basic field theory is repeatedly done such that physicists, including graduate students, may understand the essential points of symmetry breaking in this textbook. This book also contains a brief description of the lattice field theory even though it is not directly connected to symmetry breaking physics because it may hold interest for readers to be able to understand the basic point of the lattice field theory.