Book excerpt: A concise, beginner-friendly introduction to quantum field theory Quantum field theory is a powerful framework that extends quantum mechanics in ways that are essential in many modern applications. While it is the fundamental formalism for the study of many areas of physics, quantum field theory requires a different way of thinking, and many newcomers to the subject struggle with the transition from quantum mechanics. A Prelude to Quantum Field Theory introduces the key concepts of quantum field theory in a brief and accessible manner while never sacrificing mathematical rigor. The result is an easy-to-use textbook that distills the most general properties of the theory without overwhelming beginning students with more advanced applications. Bridges quantum mechanics and quantum field theory, emphasizing analogies and differences Emphasizes a “quantum field theoretical mindset” while maintaining mathematical rigor Obtains quantum fields as the continuum limit of a quantized system of many particles Highlights the correspondence between wave function—fundamental in quantum mechanics—and the formalism of second quantization used in quantum field theory Provides a step-by-step derivation of Feynman rules for the perturbative study of interacting theories Introduces students to renormalization, path integrals techniques, and more Discusses more modern topics like effective field theories Ideal for both undergraduate and graduate students Proven in the classroom