An atom or molecule illuminated by a laser has its states modified by the laser. We define a set of laser-distorted states and obtain the equation for the amplitude of the wavefunction for change of population of these states. The state equation is solved approximately in a novel gauge in the limit where the laser frequency is high, and the utility of this gauge is discussed. The equation is also investigated in the limit of intense fields where it is shown that the effect of the laser is to make the internal interactions of the atom non-local. The effect of this non-locality is investigated at large distances.AMP(B) 9 / 1 5 -~