Costello's Quantum Field Theory

Kevin Costello co-authored a textbook that puts perturbative QFT on firm mathematical footing. It includes formalizing how to work with the infinite quantities that crop up as you increase the number of interactions. The most familiar quantum field theories, like the standard model, contain additional features that may not be present in all quantum field theories. Quantum field theories that lack these features likely describe other still undiscovered properties.