Mary-who-I'm-not-dating gave this to me for Christmas.

From the back of the book:
Two millennia from now, there is no more electricity, wind engines are leading-edge technology, librarians fight duels to settle disputes, steam power is banned by every major religion, and a mysterious siren "Call" lures people to their watery graves. Nevertheless, a brilliant and ruthless leader intends to start an improbable war: a war against inconceivably ancient nuclear battlestations orbiting Earth.

However, the greatest threat to humanity is not these ancient weapons but a demented and implacable enemy who has resurrected an obscene and evil concept from the distant past.

Arranging flowers for my father-in-law's memorial service tomorrow. I'll leave this on a bench outside.