It is very hard to express how disappointed I was by this book. The premise seemed to have some potential. I will admit that it sounded a little far-fetched, but I was looking forward to seeing how Bear would manage to find some real-science hook to make it more believable. Unfortunately he didn't even seem to try.
The early Greg Bear books like Eon and Eternity were large-scale SF which had some amazingly though-provoking concepts wrapped up in stories which involved the reader. More recent books like Darwin's Radio have been more down-to-earth and closer to reality, and with a lot more grounding in current science - closer in style to Michael Crichton. Seeing the description of Dead Lines I thought it was going to be another of those Crichton-type books but soon found out that it is actually more like a Dean Koontz book. The only difference is that Koontz would have made a much better job of it.
I still think that Greg Bear is a fine writer within his genre, but on this evidence he should not try straying too far from it. There were far too many loose ends and at the most interesting points the story moves on too quickly when most readers would have probably appreciated more detail.
I really couldn't recommend this to anyone. Greg Bear fans will find it too Koontz-y, Dean Koontz fans will find that Koontz does it better.