Alright, short non-spoilery review of my thoughts on Black Howl (which may mean some spoilers for the previous books--this is me warning you... don't say I didn't warn you). 
 If you've seen the summary for the next book, you know what happens at the end of this book--in that sense, you might not want to read the summary for the next book just yet. Really, this is me trying to save you from that particular spoiler. Having said that, expect some major upheaval within the courts in Black Howl and as always, it's not the extent of Maddy's problems--far from it. There are unscheduled deaths happening and the resulting ghosts are less than coherent to say the least. Maddy will have to figure out what's happened to them if she's to stop it from happening again and again. 
 Overall, I enjoyed Black Howl. (Although--as much as I hate to say it--the bit at the end made me roll my eyes... er, the very end, that is... the thing that happened before that? A different matter completely and I AM SAYING NOTHING ABOUT IT. ABSOLUTELY NOTHING.) It's one of the few angel mythology related adult series that I enjoy and continue to read--although, perhaps, it's not for everyone.