  A quantum mean field theory of the pyrochlore lattice is presented. The
starting point is not the individual magnetic ions, as in the usual Curie-Weiss
mean field theory, but a set of interacting corner sharing tetrahedra. We check
the consistency of the model against magnetic susceptibility data, and find a
good agreement between the theoretical predictions and the experimental data.
Implications of the model and future extensions are also discussed.
