Neutron imaging is a powerful tool in the field of non-destructive testing as well as for many applications in fundamental research. This publication contains examples of how neutron imaging has been used in applications requiring the identification of (light) materials inside solid samples. It provides detailed information on how the technique has become a standard method for various applications, from the examination of nuclear fuels, explosives, electronic components and engine turbine blades to the characterization of fuel cells and geological samples.