  Interstellar dust grains efficiently absorb and scatter UV and optical
radiation in galaxies, and therefore can significantly affect the apparent
structure of spiral galaxies. We discuss the effect of dust attenuation on the
observed structural properties of bulges and discs. We also present some first
results on modelling the dust content of edge-on spiral galaxies using both
optical and Herschel far-infrared data. Both of these results demonstrate the
complex interplay of dust and star light in spiral galaxies.
