1. A method of making an electronic matrix array, said method comprising the steps of: providing at least one layer of discrete portions of a phase changeable material, said phase changeable material having a substantially non-conductive state and a comparatively highly conductive state; said discrete portions being set in one of said states; providing a first set of electrically conductive address lines on one side of said layer of discrete portions of phase changeable material; disposing said discrete portions of phase changeable material between said first and a second set of electrically conductive address lines, said second set of address lines disposed on the opposite side of said layer of discrete portions of a phase changeable material; said first and second sets of address lines crossing at an angle so as to form a plurality of cross-over points with said discrete portions of a phase changeable material operatively disposed in the areas defined by said cross-over points; and programming said layer of discrete portions of phase changeable material by converting at least selected ones of said discrete portions of said layer to the other one of said states to form selected substantially non-conductive, discrete portions of phase changeable material of said layer and selected comparatively highly conductive, portions of phase changeable material of said layer.