A sunlight collector, containing a Fresnel lens, is mounted on the roof of a building and tracks the sun during daylight hours. A concentrated beam of sunlight is directed through a light transmission channel to locations within the building where the light is distributed. The transmission channel utilizes a focusing lens for further concentrating the solar beam, refocusing lenses for correcting divergences in the beam, reflectors for redirecting the beam, and beam splitters for distributing the beam into light fixtures located throughout the interior of the building. The light fixtures contain filters for controlling the intensity and spectral content of the incoming beam, and optical elements for dispersing the beam. Additionally, the fixture contains rigidly mounted fluorescent tubes, providing artificial light, which are automatically energized when the solar light is insufficient for lighting purposes. A diffusing element is used for uniformly radiating both the artificial and the dispersed solar light from the fixture into the building interior.