I am readin Catherine Asaro's Carnelians, the lastest book in her Skolian Empire series.
It was one of the most effective weapons known.
It didn't explode. It shot no projectiles. It didn't spread chemical, biological, or physical poison It created not flames or shrapnel. It could being down empires."
I love this series and Carnelians brings together many of the elements from previous books. Carnelians is a combination of Space Opera and Science Fiction Romance. I purchased it in ebook form from Baen.