  We describe a method based on precision magnetometry that can extend the
search for axion-mediated spin-dependent forces by several orders of magnitude.
By combining techniques used in nuclear magnetic resonance and short-distance
tests of gravity, our approach can substantially improve upon current
experimental limits set by astrophysics, and probe deep into the theoretically
interesting regime for the Peccei-Quinn (PQ) axion. Our method is sensitive to
PQ axion decay constants between 10^9 and 10^12 GeV or axion masses between
10^-6 and 10^-3 eV, independent of the cosmic axion abundance.
