Response theory allows calculation of response arbitrarily close to, or far from, equilibrium. Close to equilibrium it also provides a remarkable result that us to determine how a system will respond to a driving force or a change in conditions before it is actually applied. It can tell us both the magnitude of the response and its time-evolution. The theoretical expressions relate fluctuations in the system caused by its thermal energy to properties of the system and in the linear response regime this underlies determination of diverse properties such as NMR relaxation rates, diffusion coefficients, ionic conductivity, the resistance of a circuit, thermal conductivity and viscosity. Since early developments about 80 years ago, the range of system that can be treated has grown dramatically and the extension to far from equilibrium has been enabled.1 In this talk, some novel applications of response theory will be presented.