1. A method of making a stacked integrated circuit, comprising: fabricating integrated circuit wafers for a plurality of different functional circuit layers at least to a stage of completing active devices of the integrated circuit wafers, the different functional circuit layers being in the form of one or more integrated circuit dice; wherein at least one surface of each of the different functional layers is provided with vertical interconnections such that for any two of the different functional layers, intercommunication of corresponding integrated circuit dice of the two different functional layers is enabled by aligning and connecting vertical interconnections of the two different functional lavers; selecting a subset of the plurality of different functional circuit layers for inclusion in the stacked integrated circuit; and stacking a selected subset of the plurality of different functional circuit layers, including forming vertical interconnections between adjoining integrated circuit dice.