Spin

The Grizzly Bear is huge and wild;
He has devoured the infant child.
The infant child is not aware.
It has been eaten by the bear.

A.E. Housman, Infant Innocence

Robert Charles Wilson's Spin is the best sci-fi book I've read in a while. It's hard to say what captivated me, but I remember the I-must-go-back-to-reading-it feeling from before: From when I was reading Anathem.