Polarized neutron reflection (PNR) can be used for directly determining the layer dependent magnetic moment distribution in magnetic thin film structures with atomic layer resolution. The interface roughness amplitude and layer thickness can be accurately determined and diffuse scattering measurements can be used to probe spin and structural disorder at interfaces. These capabilities are illustrated in this review of recent experimental results obtained by PNR. Measurements of the interface magnetization in X/Fe/Ag(001) structures prepared by molecular beam epitaxy (MBE) with X = Pd, Ag, Au, and Cu are compared with the predictions based on theoretical calculations which take into account the measured interface roughness. For the case of strained fct Ni/Cu(001) structures prepared by MBE, the thickness dependence of the magnetic moments reveals a strong variation in Ni moment which is reflected in the variation of the ratio of orbital and spin moments with thickness determined from x-ray circular dichroism (XMCD) measurements. It is shown that the magnetic moments determined from applying sum rules to the XMCD results agree with the absolute moments determined by PNR using the same test sample. PNR can be used in these structures to determine the degree of uniformity of the magnetization profile across the depth of the Ni layers, so allowing a test of models which assume that the reduced magnetization to be of interfacial origin. The thickness obtained from an analysis of the wavevector dependence of the reflectivity is shown to agree with that obtained from x-ray reflectivity measurements. Measurements of the layer dependent moments in FeNi/Cu/Co spin valve structures are presented and it is shown that by comparing the PNR measurements with superconducting quantum interference device magnetometry measurements of the total sample moment it is possible to determine the interface moments on an atomic scale. Vector magnetometry measurements of the layer dependent magnetic moment orientations are shown to provide a powerful approach to studying spin orientations in ferromagnetic (FM)/nonmagnetic (NM)/FM trilayer structures. For epitaxial FeNi/Cu/Co(001) spin valve structures with negligible coupling, it is shown that the layer dependent moment orientation and amplitude can be determined with percent precision as a function of applied field.