Enzymology is the study of enzymes — the science of the protein catalysts that make life’s chemistry possible. It spans their structure, how their active sites bind substrates with exquisite specificity; their kinetics, the mathematics of how fast they work and what slows them; their regulation, the feedback loops and modifications that switch them on and off; and their applications, from the amylases of brewing to the engineered enzymes of detergents and biofuels. Food science is applied enzymology throughout — every fermentation, every cheese ripening, every browning reaction, every digestive process is enzyme action. The field gave us the lock-and-key model, Michaelis–Menten kinetics, and the industrial enzyme business. To study enzymology is to study the machinery room of biology, where the actual work gets done.