By training, Eric Shirley is a theoretical solid-state physicist, with experience in atomic-structure calculations, band-structure calculations, and many-body theory. He has been involved in calculations of the optical spectra of solids throughout the electromagnetic spectrum, from the far-infrared to the hard x-ray region. His research interests lie in computational physics, which relies heavily on the use of extensive computational resources, as well as mathematical physics, which is limited only by the abilities of the practitioner. Beyond studying the main moving parts of solids, i.e., electrons, having a background in mathematical physics (of the applied, down-to-earth sort) has helped Shirley and his colleagues study the wave propagation of photons in photonic crystals and practical optical systems such as collimators, radiometers, and telescopes. These research endeavors have led to successful understanding of problems pertinent to communities ranging from semiconductor manufacturing to climate science.