Authors: Nicholeen Viall (NASA/GSFC), Michael Kirk (NASA/GSFC), Craig DeForest (SWRI) and Sarah Gibson (NCAR)

The Polarimeter to UNify the Corona and Heliosphere (PUNCH) mission was launched on March 11, 2025, and is in the process of commissioning. We describe the science of PUNCH and how the entire community can get involved. PUNCH, with its high temporal and spatial resolution and unprecedented coverage of the inner heliosphere, will unravel the complexity of cross-scale coupling. In particular, PUNCH will provide new understanding of mesoscale structures in the solar wind, coronal mass ejections and stream interaction regions by measuring and tracking their characteristics through the inner heliosphere.  PUNCH is especially excited to find new ways to UNify the heliosphere, and find synergies with other Heliophysics missions.