Abstract With this paper Grimm and Storer introduced importance sampling to the field of quantum Monte Carlo. They had earlier used numerical quadrature for estimating the integrals required in evaluating energies in a diffusion-like path integral iteration scheme for solving the Schrödinger equation.0 This was extended to larger numbers of particles and higher dimensions with use of Monte Carlo methods. In conjunction with this they recognized they could take advantage of prior knowledge of the general form of a wavefunction to obtain more accurate estimates of the eigenvalue Eo .