The pairing resonance is an anomaly in the tunneling density of states (TDOS) of superconductors driven to the normal state, at low temperatures and high magnetic fields, by the Zeeman effect. I will review experiments on thin films and their theoretical explanations. The position and shape of the pairing resonance depend on the strength and direction of the applied field, and on material properties such as the spin-orbit scattering rate 1/\tau_{so} and the Fermi-liquid parameter G^0, which accounts for the renormalization of the spin susceptibility due to interactions. We can therefore determine \tau_{so} and G^0 from measurements of the TDOS. As another application, I will discuss measurements of conduction electron polarization in ferromagnetic films.