  We present a unified theory to treat conservation laws in light-matter
interactions. It can be used to describe and engineer the transfer of any
measurable property from the electromagnetic field to any object. The theory
allows to explicitly characterize and separately compute the transfer due to
asymmetry of the object and the transfer due to field absorption by the object.
It also allows to compute the upper bound of the transfer rate of any given
property to any given object, together with the corresponding most efficient
illumination which achieves the bound. Due to its algebraic nature, the
approach is inherently suited for computer implementation.
