In a series of pioneering papers in the 1980s that relied on numerical simulations, Marc Davis, George Efstathiou, Carlos Frenk, and Simon White provided a powerful new tool for comparing theory and observation on cosmological scales. They then used that tool to validate the “cold dark matter” theory of cosmic growth. Today virtually every aspect of astronomy relies on numerical simulations, and cold dark matter is a fundamental component of the standard model of cosmology.