The Morphology, Color, and Gas Content of Low Surface Brightness   Galaxies
  Recent surveys have discovered hundreds of low surface brightness galaxies, systems with central surface brightness fainter than 22.0 B mag arcsec^-2, in the local universe. Plots of the surface brightness distribution - that is, the space density of galaxies plotted against central surface brightness - show a flat space density distribution from the canonical Freeman value of 21.65 through the current observational limit of 25.0 B mag arcsec^-2. It is therefore extremely important to understand these diffuse systems if we wish to understand galaxy formation and evolution as a whole. This talk is a review of both the known properties of low surface brightness galaxies and of popular theories describing the formation and evolution of these enigmatic systems. 
K. O'Neil