From these data, together with further measurements by the same technique from Furman et al. (20) and Kaufman et al. (21), as well as measurements by orthogonal methods using neuropathological approaches in human disease from Gómez-Isla et al. (22) and longitudinal in vivo tau positron emission tomography (PET) imaging, we here determine the rates and rate-determining steps of tau accumulation during AD. The gene discussed is MAPT; the disease is Alzheimer disease.