Undermountain is completely different from anything that I've ever read before, in a good way! I really enjoyed reading it! Eric Edstrom has created a very awesome and interesting world beneath the Canadain Rockies (beneath all of the Earth's major mountain ranges actually). The thought that there could be an entire civilization of Bigfoots (Bigfeet?) down there is really great. I had started reading this one before bed one night and before I knew it I was 100 pages in and it was 1 am. Even though I had just meant to read a few pages. This book kept me up the second night as well, trying to get it finished but I just couldn't because it got too late, so I finished it the next morning before doing anything else. So very hard to put down. I just had to know what would happen next.I liked most of the characters (all but Bronson and Shaggy, but I don't think you are really supposed to like them). They all really grew up and matured after their experience of being captives. Danny became more of a leader, Em less selfish, Wa more serious (but still a joker), Breyona more calm and Shiv turned out to be more than expected from him since he liked being in Undermountain. I like Grizz the bigfoot, how he tried to help the humans even though he had been ordered not to.All in all, it's a great story, one with a lot of imagination put behind it. It's unique and a huge page turner. It's a great YA book and would be ok for even younger teens. There are a few twists, but I really wasn't ever sure what to expect, which is really good. Very enjoyable and I would definitely recommend this one to fantasy/sci fi lovers! You should check it out!