The electrostatic properties of crystals of or-glycine have been obtained from extensive X-ray diffraction data collected at approximately 23 K and carefully processed, including corrections for scan truncation losses, anisotropic extinction, and multiple reflection. From a multipole parameterization of the X-ray intensities we have obtained an unusually precise-and we are confident, accurate-model of the total electron distribution in the crystal including the topological features, atom and group charges, the dipole moment for the glycine zwitterion, electrostatic potentials, electric field gradients at the nucleii of the three hydrogen atoms of the ammonium group, and intermolecular electrostatic energies within the crystal. We have also calculated the total interaction energies involving the six distinct types of intermolecular pairings and examined these energies in terms of the molecular arrangement.