  The local structure study reveals important aspects of the physical
properties, because it is closely related to the electronic structure. Standard
crystallographic analysis based on a space group fails to observe disorder in
the crystal structure. Many functional and industrial materials have disorder,
because of the optimized modifications of crystal structures such as the
substitution of an element. Doped elements inevitably induce local strains in
the matrix. Some neutron total scattering results are reviewed to show the
local functional properties of solids from optical recording to negative
thermal expansion to Mott transition materials.
