I was thinking about buying the e-book of this, since it didn't appear in my library catalog forever. But eventually, one day it popped up on the list, much to my surprise. I was pretty excited to read it; I'd seen some really good reviews and some bad ones, and I think I landed somewhere in the middle. The covers of this series are actually really pretty; the second book, Hover, is done in purple and I love it. The best thing about Gravity is the concept. The tagline on the book (Don't. Ever. Peak) just begs you to pick it up and see what that's all about. I loved the idea of aliens needing certain nutrients to survive on the earth and Taking them from humans in the middle of the night while they slept. Just the thought of it is definitely creepy, but an interesting idea, right? 
 It took me a long time to really to get into the story after I picked it up. The world-building certainly isn't bad; by the end of the book I felt like I understood pretty much everything that went on and the different technology that was used. But for the first hundred pages or so, it felt like a lot of information was given to the reader in a really short amount of time. Gravity is about 280 pages or so, and I felt like it could have been longer to give it more substance, which is where the real problem lies. 
 It has always been my opinion that you can have the best writing, the best plot and the best world-building ever, but if your characters are flat, or so-so at best, then almost everything else will fall apart. I absolutely have to be invested in the characters to enjoy a book, which is why I almost always prefer a first person narrative; because it feels more personal. Gravity is in Ari's POV, and to an extent, I enjoyed her as a protagonist. I liked her relationship with her best friend, Gretchen; I appreciated how strong it was after having read so many books lately with false, flimsy friendships. But at the same time, everyone in Gravity was just alright. 
 My main gripe is the romance. Jackson was probably the character that fell the most short to me. I felt like Ari begins to trust him way too early in the story, pretty much almost immediately deciding to help him even though it goes against everything she's ever been taught; trusting Ancients. And their relationship just never felt real. They were decent as a couple, I guess, but I felt like more time could have been devoted to deepening their bond so I wasn't getting this 'meh' feeling constantly. At one point in the book, Ari finds out the Ancients' reason for coming to earth is believed to be false - running out of water on their home planet - and Ari doesn't ever just ask Jackson about their real reason for coming. It was frustrating. 
 Despite my complaints, by the second half of Gravity I was engrossed in the story and the war that was going down between the Ancients and the humans. I liked the occasional twists West threw into the story; some of them were easy to predict, and other's weren't. At some point in the future, I'm sure I'll pick up Hover and hope that the romance deepens. 
 3.5 stars