Recent magnetic, optical and neutron scattering experiments made possible by the availability of high purity samples are providing increasingly detailed information about the electronic structure of the rare earth metals. The first calculations for the paramagnetic state of these fascinating metals have long served as a valuable heuristic model for understanding many earlier experimental results. It is expected that more accurate calculations for the magnetic ground state will be equally valuable in fostering the traditionally fruitful interaction between theory and experiment. Such calculations present a formidable challenge since they require a relativistic approach to spin polarization and a suitable treatment of the highly localized 4f-shell. The calculations can be guided by comparison with precise experimental results and by self-consistent calculations for non-magnetic metals with similar electronic structures. In this paper we review the present status of band structure calculations for the rare earth metals, and give details of a self-consistent, relativistic, ferromagnetic calculation for gadolinium