  The leading corrections to Fermi liquid theory for non-equilibrium
quasiparticle transport near a Cooper instability arise from the virtual
emission and absorption of incipient Cooper pairs. We formulate the corrections
to the Landau-Boltzmann transport equation starting from Keldysh's field theory
for non-equilibrium, strongly interacting Fermions. The theory is applicable to
quasiparticle transport in conventional and unconventional superconductors,
dense nuclear matter and the low temperature phases of liquid $^3$He.
Validation of the theory is provided by our analysis, and quantitative
agreement between theory and experiment, of the excess attenuation of zero
sound in liquid $^3$He near the superfluid transition. We propose an additional
experimental test of the theory based on the effects of a Zeeman field on the
spectrum of pairing fluctuations for the Cooper instability in spin-triplet
superfluids.
