Quite soon, the world's information infrastructure is going to reach a level of scale and complexity that will force scientists and engineers to approach it in an entirely new way. The familiar notions of command and control are being thwarted by realities of a faster, denser world of communication where choice, variety, and indeterminism rule. The myth of the machine that does exactly what we tell it has come to an end.

What makes us think we can rely on all this technology? What keeps it together today, and how might it work tomorrow? Will we know how to build the next...