This talk revisits classical kinetic theory from the perspective of exterior calculus and geometric mechanics. I review how the Boltzmann and Kac equations can be formulated using differential forms on phase space. In particular I'll discuss how this geometric viewpoint clarifies the role of entropy, the separation of reversible and irreversible mechanisms, and the structural relation between kinetic and hydrodynamic descriptions. The presentation aims to highlight both the conceptual advantages of exterior calculus in kinetic theory and potential directions for further development.