Last fall I read and enjoyed the first book in this series, Ashfall. It was a compelling story that kept me up until 3AM. I knew I had to read Ashen Winter and it was worth the wait. I worried that it wouldn't be as good the first book, that Mullin wouldn't be able to sustain the story and keep it interesting and well-told. I didn't give him enough credit. *bashes self on head* 
 I started the book early in the day which was a good thing because it is long, 576 pages. A few times it dragged, some scenes could have been shortened in my opinion, but overall I wouldn't change a thing about this book. It starts shortly after Ashfall ended; Alex is determined to go look for his parents while Darla thinks they should stay where they are but insists on accompanying him. Naturally, the search doesn't go as planned, there are many things that go wrong, a few that go right and even a reunion or two along the way. At times I had to remind myself that Alex was only sixteen; he was impulsive, emotional and reactive. But that's part of the beauty of Mullin's writing; I got so caught up in the story telling and what was happening that I'd be getting upset with Alex and mentally fussing at him not to do this or to please do that just as if he were a real person. Although Alex has matured a great deal during the months since the eruption, he's still young and still sometimes reckless. 
 The story grips you and makes you feel what it must be like to be in Alex and Darla's circumstances. Mullin did a lot of research and it shows but he doesn't hit you over the head with it, it's part of the story. It's amazing, detailed, realistic world building. I particularly appreciated his depiction of someone with autism; it was honest, respectful, and realistic. That character is a good addition to the story and I hope to see more of him in the next book. In addition to all of the technical details that contribute to the reader feeling like they are there, Mullin doesn't forget about the emotional aspects. You feel the cold and hunger, the desperation to survive, and ultimately, the costs of the choices we make. Every choice has a consequence, some positive, some negative, some neutral, but there is always a reaction and sometimes there are no good choices or answers. Alex learned that in Ashfall, but it gets brutally reinforced in this book. It's not a happy, easy, or comfortable book. But is is, I believe, an honest look at survival and the choices we make. There's currently one more book left in the series but the world Mullin has created could easily support an entire multi-book series, with or without Alex and Darla. 
 If you want a compelling, engaging, well-told story that makes you both think and feel, then you want to read Ashen Winter. 
 I received an eARC from the publisher.