MAS solid‐state NMR spectroscopy yields atom‐specific information on the structure of aggregates such as amyloid fibrils formed by the Alzheimer's disease peptides Aβ,9 α‐synuclein,10 or tau.11 NMR spectroscopy is particularly sensitive to changes in the local electronic environment and allows ligand binding to be probed. This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.