As described in his landmark paper on holography, "A new microscopic principle", Denis Gabor sent coherent light through a transparent plate with some black letters on it. The light that was diffracted by the letters then interfered with non-diffracted waves.
In Thomas Young's famous double slit experiment (or at least the way it is taught today), coherent light is sent through two small slits. Some light is diffracted when passing through and interferes with non-diffracted waves. Can this be seen as an in-line holographic setup? If I were to record the resulting pattern of light and dark, could I reconstruct the two slits?