The interstellar medium (ISM) is a turbulent, multi-phase, magnetic environment. Magnetic fields thread our Milky Way Galaxy, influencing interstellar physics from cosmic ray propagation to star formation. The magnetic interstellar medium is also a formidable foreground for experimental cosmology, particularly for the quest to find signatures of inflation in the polarized cosmic microwave background. Despite its importance across scientific realms, the interstellar magnetic field and its influence on Galactic processes are not well understood. I will discuss new ways to probe interstellar magnetism, the phase structure of interstellar gas, and the link between the two, with a particular focus on morphology: how the spatial structure of gas and dust encodes information about the physics of the ISM.
