Abstract: Bigger telescopes are usually better telescopes…. but not always. In this talk I will explore the ghostly world of large low surface brightness structures, such as galactic stellar halos, low-surface brightness dwarf galaxies, and other exotica such as supernova light echoes. These objects are nearly undetectable with conventional telescopes, but their properties may hold the key to understanding how galaxies assemble. I will describe why finding these objects is important, and why it is so devilishly difficult.