Book excerpt: Many courses on modern quantum field theory focus on the formulation and application of field theory, leaving topics related to symmetry underdeveloped. This leads to students often having an incomplete understanding of symmetries. Filling this gap, Symmetries and Symmetry Breaking in Field Theory sheds light on various aspects of symmetry in field theory. The book presents a broad selection of important topics, including constraint theory, generalized Pauli–Villars regularization, the measure approach to anomalies, zeta function regularization, and anomalous gauge theories. The author explains how some classical symmetries are broken by anomalies and how other symmetries of the theory are spontaneously broken. He discusses all of the ideas in as simple a way as possible.