The authors present a new field theoretic formulation of the quantum mechanics of disordered systems. The problem is converted to an explicit field theory by changing variables in the functional integral over all random potentials to an integral over all possible wave-functions. Unlike previous formulations this field theory has the novel feature of having the 'right' sign for the coefficient of the phi ⁴ term. Thus the important excitations are kinks rather than instantons. In addition, it exhibits singular solutions with finite action. The method is illustrated with an exact calculation of the asymptotic density of states in a one-dimensional gaussian white noise potential.