The extended infrared celestial emission is due to three main sources: zodiacal dust, large discrete objects in the galaxy, and inter-stellar dust. As viewed from earth orbit, the thermal reradiation of sunlight absorbed by dust in the solar system produces a pervasive IR background that peaks roughly along the ecliptic plane, where the density of dust is highest. Much-smaller-scale structure has also been ob-served in both the visual and infrared. Between 7 and 30 Am, H II regions are the brightest discrete objects in the galaxy. Dust mixed with and sur-rounding gas ionized by the embedded hot star(s) absorbs the visible and ultraviolet stellar radiation and re-emits the energy in the infrared. These regions are large and if close to the sun can subtend significant angular areas of sky. The emission from the interstellar dust produces a filamentary background that is consistent with dust in thermal equilibrium with the interstellar radiation field at far-IR wavelengths. An additional emission mechanism is needed, however, to account for the shorter-wavelength observations. The galactic sources combine along the line of sight to produce an intense band of emission, centered on the galactic plane. Structure in all of these backgrounds creates a clutter problem for an orbiting IR telescope.