Magnetism and Morphology in the Interstellar Medium

The interstellar medium (ISM) is a turbulent, multi-phase, magnetic environment. It is home to vastly different gas phases, from cold, dense clouds to hot, tenuous plasma. Magnetic fields thread this interstellar environment, helping to sculpt galaxies through their influence on a diverse range of physics, from cosmic ray propagation to star formation. The magnetic ISM is also a formidable foreground for experimental cosmology, especially for studies of the polarized cosmic microwave background. 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.