With certainty scaling in silicon is going to hit a wall -technologically or economically. While we do not know exactly when this is going to happen, "approximately a decade from now" is a pretty common guess. Hence it is prudent to imagine and investigate alternative ways to create electronic systems that may have a chance to lead us "beyond silicon". At present there is no clear path at all. Only open-minded and imaginative research has a chance to overcome the foreseeable impasse. (c) 2006 Elsevier Ltd. All rights reserved.