Light echoes from Galactic transients offer a powerful new tool to measure distances, map Galactic structure, and probe the properties of interstellar dust. I will discuss the physics of dust scattering using examples of the extraordinarily bright echoes from Circinus X-1 and V404 Cygni, from a Wisconsin perspective on dust physics, and the prospects for future advances in X-ray Dust Tomography.
X-ray Dust Tomography: A New Frontier in Galactic Exploration