The unique potential of neutron scattering in structural biology arises from the strong interaction of neutrons with hydrogen (H) and its deuterium (D) isotope. This property makes the information available from neutron scattering unique and a valuable complement to data obtained from other structural techniques. Individual hydrogen/deuterium atoms are visualized in neutron density maps from crystallographic data at the resolution typical of most protein structures (2.0 -2.5 Å). Using H/D exchange and contrast variation, proteins and nucleic acids are sequentially modeled and mapped in large biological complexes using small angle neutron scattering. Protein-membrane interactions are revealed using reflectometry and protein and water dynamics measured using spectroscopy.