The magnetic phase diagram of CeSb, which has been determined by neutron diffraction and other experimental techniques, is briefly reviewed and related to some of the theoretical models that have been developed to account for it. The results of neutron diffraction studies of Nd metal are also summarized. The data is shown to be consistent with the theoretical prediction that between 9 K and TN there exist two magnetic phases (TN = 19.9 K; T2 = 19.3 K). A discussion is given of some of the difficulties that arise when trying to design a model of the magnetic structure that fully explains all the experimental data. Attention is paid to the prediction of renormalization‐group theory that two dimensionally modulated magnetic structures exist in Nd. It is suggested that although there is no direct experimental evidence for the existence of such structures in Nd, none of the existing experimental data preclude this possibility.