What the first two novels in the Across the Universe trilogy lacked for me was pretty much completely made up for in this final book. Though I hate to admit that I still found the characters to be pretty underdeveloped and feeling kind of hollow, Revis' writing has significantly improved between the first book and this book, and now I'm really glad that I began reading the first. 
 It was the premise of the first book that intrigued me, not the writing or the characters, but the premise. The plot led to the sequel in a way that made me curious, but the second book wasn't much better than the first. Still, the plot and the premise was enough to keep me invested, and so I picked up Shades of Earth with little expectations. There's something about this book that is vastly superior to the other two, though. It could be the world-building, as Revis managed to make Centauri-Earth seem visceral, even though we only had a very small view of it. The characters seemed to have a little extra depth, although I was still underwhelmed by Amy's relationships with her parents and Elder (Although, Elder's jealousy in the first half of the book was hilarious, purely because it felt so ridiculous. "Ooh, the girl I love for no reason whatsoever is talking to another boy, I must feel jealousy!"). The plot was smooth, and while I can't say everything that happened in the story made me happy, as someone who endured the first two books, I was satisfied with how it ended. 
 I guess my biggest problem with this book is that it's lacking. The other two I could fault more (what with the first book putting a neon sign over the antagonist's head maybe a quarter of the way into the story, and the second giving us a very emotionless and boring romance), but while I'm satisfied with where the story took me and where the characters ended up, I'm still dissatisfied with it on a whole. It was better than I'd expected, but it still wasn't enough, if that makes sense. Perhaps it's purely the characters, with their cardboard emotions and very clear instructions on how to interact with one another. They didn't feel alive to me, and sometimes they just didn't make sense. They weren't true to themselves all the time, and sometimes their actions seemed less like what the character would actually do and more like what was needed for the plot, which is disappointing. 
 I should probably mention that I kind of saw the ending coming, too, which was a letdown. The last few chapters felt forced, running through the aftermath of the end of the big final conflict so we could see what happened next, but not doing so with very much emotion or detail. So I guessed what was going to happen next, and I was right. It wasn't too bad, I suppose, since that element didn't feel very well executed in the first place, but still, that's a thing that happened. Also, that probably doesn't make ANY sense considering how vague I'm writing this review, but I'm trying to leave out spoilers and I'm too lazy to hide them. 
 In any case, I am glad that I read Shades of Earth. I'm glad to see the quality of Beth Revis' writing improved, happy to have wrapped up plotlines that began in Book One, and even pleased with a nod to the first book in Amy's dialogue. I do wish it had been a bit better, a bit fuller, even, but with the preceding books being so lackluster, I'm not disappointed.