In collaboration with his father, S. G. Gorlin, a mechanical engineer who designed hydraulic systems for gasoline engines at the beginning of the century, Richard Gorlin developed a formula to calculate the area of stenotic cardiac valves and congenital heart chamber defects. The “Gorlin formula,” still considered the “gold standard” for diagnosis of critical heart valve obstruction, was crucial to the evolution of cardiac surgery because it allowed proper case selection and contributed greatly to the design of artificial valves.