Originally developed more than four decades ago for imaging non-refracting radiation such as x-rays, gamma-rays, and neutrons, today coded apertures are poised for new applications in other domains of the electro-magnetic spectrum. Boasting excellent angular resolution, wide field-of-view, negligible image distortion, and light weight construction, coded apertures are increasingly attractive for certain IR and optical applications. Successful exploitation of the coded aperture technique to these new venues will require the systems engineer or designer to understand the fundamental principles of imaging with coded apertures. This presentation explores the special properties of coded aperture masks, the algorithms used to design them, the signal processing algorithms used to decode recorded data, as well as important design considerations for a successful system. The targeted audience is the engineer with minimal prior working knowledge of coded apertures who wants to understand the technology sufficiently well to reliably assess applicability for present and future needs.