For the last three decades or more, computer processor speeds have grown at the rapid pace expected by Moore's Law. This tremendous increase has allowed for there to be great advances in the range and sophistication of applications supported, and tasks that some years ago could not even be performed on specialized scientific supercomputers costing millions of dollars are now routine affairs even on personal desktop machines. However, it has been observed that sequential uniprocessor computing is approaching a fundamental restriction on its performance--the speed of light. Since processor speeds are already up to the gigahertz level and transistor sizes on chips are already in the micron range, it is felt that the current technology is unlikely to sustain the rate of progress for much longer before coming up against the laws of physics. Of course, it can always be hoped that a different type of...