We will develop and characterize a common-path or Sagnac interferometer with CCD array detector that can be used as a space-borne or field spectrometer from the UV to the IR region of the spectrum. The specific innovation is that the entire interferometer assembly (beamsplitter, mirrors, lens, and associated optics) will be fabricated as a monolithic, solid block. The importance of this innovation is that very compact instruments can be built for field and flight assignments that will require no adjustments beyond initial assembly since they cannot become misaligned. In addition, the dispersion effects of thick beamsplitters will be eliminated, thus restoring the large field of view inherent to the common-path interferometer. The instrument has an inherently wide range of design flexibility. We anticipate that it can be used for spectrophotometry, spatially resolved spectroscopy, and moderate resolution spectroscopy over a wide spectral range. The large field of view with respect to grating spectrometers will make this an invaluable instrument for many applications.Spectroscopy of chemiluminescent and bioluminescent materials, high altitude balloon and rocket observations of atmospheric constituents, spectroscopy and spectrophotometry of planetary atmospheres and surfaces. The instrument will also compete favorably with grating spectrometers for a wide range of laboratory spectroscopy problems.CCD, FTS, spatially modulated fourier transform spectroscopy