**edited 02/01/14 
 Welp, the pun must be spoken: this book left me cold. 
 Most likely I'm writing this review just for me, but if not, then: 
 --If you're new to The Dresden Files, don't start here. The first books are a little shaky, so if you're not a purist, I suggest trying Summer Knight or Dead Beat. 
 --If you've read the last 13 books and are trying to gauge this one, just go pick up the book. You know you're going to anyway. Also, although my review is Cold Days-spoiler-free, my "status updates" are a little spoilery. 
 --If you've already read this and are interested in other peoples' reactions, if you're a fan...well, I had some issues with this book. Please don't hurt me. One of the impressive aspects of the series is that it appeals to a very wide audience, and I'm apparently the lone voice cheering on Ghost Story, which pretty much predicts my reaction to this. If you're bored enough to read this, I suggest scrolling to the bottom instead--I have a compendium of currently unsolved mysteries and my favourite crackpot theories. 
 The truth is that I simply did not enjoy reading this. Put it this way: I read at the gym, and when I was trying to read Cold Days, I skipped, procrastinated, and even read scientific papers to avoid jumping back into Cold Days. 
 In terms of plot, there is a lot of action. A lot. Harry Dresden's life has a pattern: three or four days of hectic action, injuries, and crisis, followed by six months or so of downtime and recovery. Here, the timespan is constricted: other than the first chapter, this entire 500-page book takes place over less than 36 hours. It is probably also one of the biggest game-changing books apart from #3 and #12. We finally get to see the face of the Big Bad who has been manipulating so many of the events since Storm Front (and it's exactly who you think it is). Actually, I thought it was a bit of a letdown, as I don't find that particular paranormal particularly scary. (view spoiler)[I basically find Lovecraftian critters hilarious rather than scary. Maybe I read Lovecraft too young, but his beasties always remind me of this three-part flip book I had as a kid where you could put the head of a crocodile on a cow, etc. I also thought it was a total letdown that Dresden was so easily able to defeat them-- how will they be remotely threatening as the Big Apocalyptic Baddies? (hide spoiler)] We find out more about Demonreach and Rashid. A few more mysteries get opened up, and certain characters' lives are changed irrevocably. Perhaps the biggest change, however, is the power level. Dresden has continued to "power up" throughout the series, but here he finally swaps from an impressively strong mortal to a supernatural mover and shaker. And one consequence that I loved from this is that, although the conflict between the underdog and the big strong supernatural continues, Dresden is no longer the underdog. Instead, he's the one underestimating his enemies and getting outwitted by his magical inferiors. Maybe it's due to my current ambivalence about Dresden, but I loved this. (view spoiler)[Favorite moment? Dresden is totally pwnd by a bunch of tiny faeries. Awesomeness. (hide spoiler)] 
 My lack of enjoyment here made me try to understand what I love about the Dresden Files. I love it in the same way I loved the Harry Potter series: a wide, imaginative, and well-built kitchen sink world, a huge host of entertaining characters, plenty of humour and absurdism, and--joy of joys--a huge and well-thought-out plot arc with tons of clues sprinkled into the various books. 
 ... 
 Due to my disapproval of GR's new and rather subjective review deletion policy, the rest of this review can be found on Booklikes.