Lover Eternal (Black Dagger Brotherhood, Book 2) by J.R. Ward
I couldn't help it, I had to pick up the next book in this series! It was as good, if not better, than the first one. This book is about Rhage and Mary, but also continues the storyline of the Lessers and their plans to take down the Brotherhood.
The writing in this book (and the 1st one) is great, and the plot is terrific. I am fighting the urge to go straight to the next one! But I have other books to read and send out :-D