Holographic optical elements are a critically enabling component of modern spectroscopy and spectral imaging systems. While the most common holographic elements are essentially those discovered in 1962 by Leith and Upatnieks, several decades passed prior to the effective integration of holography and sensing. Over 5 decades Emmett Leith was a prime mover in both the birth and the maturation of computational holographic sensors. Recent demonstrations of the unique utility of holographic filtering suggest that continued improvements in materials and recording processes for Leith's original concept will yield tremendous results. This paper describes the multiple order coded aperture (MOCA) spectrometer as an example of the potential for advanced holography in computational sensors.