  We report Knight shift experiments on the superconducting heavy electron
material CeCoIn$_5$ that allow one to track with some precision the behavior of
the heavy electron Kondo liquid in the superconducting state with results in
agreement with BCS theory. An analysis of the $^{115}$In nuclear quadrupole
resonance (NQR) spin-lattice relaxation rate $T_1^{-1}$ measurements under
pressure reveals the presence of 2d magnetic quantum critical fluctuations in
the heavy electron component that are a promising candidate for the pairing
mechanism in this material. Our results are consistent with an
antiferromagnetic quantum critical point (QCP) located at slightly negative
pressure in CeCoIn$_5$ and provide additional evidence for significant
similarities between the heavy electron materials and the high $T_c$ cuprates.
