Singularity Sky by Charles Stross is his debut novel. On a backwater planet that is part of the New Republic (a totalitarian and relatively backward ludditist civilization) one day it begins raining telephones. When someone picks up a phone, it answers that it is “The Festival” and offers to exchange advanced technology for information–“Entertain us.” speaks the phone. Parts of this advanced tech includes cornucopia machines–nano-tech devices to make just about anything for which raw materials are available. All of this tech rapidly leads to a revolution and the rulers of the New Republic think this calls for a military response. Unfortunately for them, they really don’t understand the situation at all.
Singularity Sky is set roughly 400 years from now. Part of the background is that sometime in the relatively near future a technological singularity occurs. Stross works his way around the problem of nothing being left after this by having this be a partial singularity. Whatever part of tech that bootstraps itself rapidly gains vast power and promptly sends 90% of humanity off to various star systems through worm hole devices. It leaves behind the warning:
I am the Eschaton. I am not your God.
I am descended from you, and exist in your future.
Thou shalt not violate causality within my historic light cone. Or else.
Basically, it has put in enough rules that prevent its own causality destruction and so the arising of other complete singularities. This is a fairly clever device on Stross’ part.
When the New Republic decides to come very close to using causality violation (time travel) to deal with the perceived threat of the Festival, the Eschaton and agents becomes involved–adventure ensues.
I enjoyed this book quite a lot. It is brimming with ideas and pretty well written to boot.