Some of the familiar kinds of optical designs for the visual region of the spectrum take on new meaning when applied to infrared problems. The availability of high indexes of refraction, for example, accentuates byways of optical design in the visual into quite unusual results in the infrared. As a first example, the ROsch combination of catadioptric system derived from the Schmidt telescope leads to a kind of wide-field system of low aperture ratio and low obscuration, although at a sacrifice of compactness. In another such instance, it is feasible to design an optical system in the IR that can illuminate some appropriate form of detector from a major fraction of a 4-pi solid angle over a field of view of appreciable size. Similarly, it is possible to design a form of retroreflector for the IR that has a 4-pi field of view, as for the Luneberg sphere. Further examples of special design for the infrared are discussed, including all-refractive, and all-reflective and catadioptric combinations. The author reviews some of these useful facets of optical design where appropriate infrared materials can be employed, and suggests how some of these forms may be applied to infrared problems.