Review posted here. 
 As I've said before, I was part of the Gallagher Girls since almost the very beginning. I can't even remember when I first read LYKY, but I remember picking it up because it had a cute cover, an intriguing title, and an even more interesting description. I remember loving it. I remember obsessively checking Ally Carter's website daily to make sure I wasn't missing out on any GG news. I remember being so excited about this series and sharing it with my mom. I don't remember it becoming a massive hit, but then suddenly, I realized I wasn't the only one waiting anxiously for each new installment of the adventures of Cammie, Bex, Liz, and Macey. Suddenly, I was part of something bigger, something that even the word fandom can't quite encapsulate. I was a part of the real Gallagher Girls. I was part of a family of readers who could imagine perfectly fitting into a world of spies, lies, and danger. That's why this review is pretty hard to write. How do you say goodbye to something that means so much to so many? How do you say properly critique something when you know whatever you say will be considered aimless gushing? The answer, I suppose is that you don't. You don't say goodbye. You don't give a proper critique of the technical aspects. You gush. You cry a little. You laugh. And you say, see you on your next adventure. 
 I think one of the reasons the Gallagher Girls series is such a hit is that Cammie is one of the best narrators a book could have. Sure, as this is in first person, we know Cammie's story will be a little unreliable, as all first person narration is. However, when the narrator is also a spy-in-training and is actually recording every event, every conversation for use in Official Government Documents, you trust her a little bit more. Cammie is the chameleon. She blends in the background in every mission (or she's better than the rest, at least). Well, she's also a chameleon for the fact that she's one of the most relatable characters I've ever read in ya. Cammie's story is so diverse and rich in experience that I dare you to find someone who doesn't share something with her, from the death of her father; to her feelings of invisibility and later, inadequacy and insanity; to her guilt, fear, and anger of both the future and the past; to her connection with her mom and aunt; her friendships; her romantic relationships... I could go on, but I think that's a good list. Cammie will always be someone I feel like I can go to when I'm having a problem because I feel like she and her three supporting musketeers have solved just about every problem a girl can possibly have. And if not, they certainly have gifted me with the tools to solve my problems. 
 One of the best things about Cammie through the series has been her remarkable ability to change and adapt, which is another aspect of her chameleon-ness. With long series, I think it can be hard to have your characters change realistically without intense reader backlash. We always love the characters in the first book, but sometimes, it's hard for a reader to accept the changes an author creates in sequels. Not in this case. Cammie's been through the ringer, emotionally, physically, mentally. By United We Spy, she's incredibly different from the innocent young girl we met in LYKY; however, she's also the same in many ways, a feat I attribute to her extraordinary strength of character. Even when at her most vulnerable and broken, she's strong. I find Cammie one of the most remarkably admirable characters in any book of any genre. 
 Next, we have Cammie's stalwart roommates, teammates, cheerleaders, and minions: Bex, Liz, and Macey. A tougher and more loyal group of sidekicks there never was, and the amazing thing is that I actually feel pretty guilty calling them Cammie's sidekicks because each girl goes through her own intense development and trials throughout the series. They're not just yes-girls. They're their own main character in their own story that Ally for whatever reason chose not to write. But the fact that "Double Crossed" exists and that each girl had her moment[s] in the series proves they're leading ladies in their own right (darn right I stole that concept from The Holiday!). Like Cammie, each of the three has moments of fragility intertwined with moments of hardiness. There are times in these books when I wondered if one of the girls would fall prey to jealousy or weakness or fear. I wondered if one of them would ever give up on Cammie, give up on the Gallagher Girls. There are occasions when I could see them deciding it was too much effort. Macey and Liz, especially, had tastes of life outside of spying, and I wondered if they would ever just quit. They did not. They are Gallagher Girls. They stuck with it to the end because their stubbornness and their love for one another just wouldn't let them give up. If there's anything I admire in a person, fictional or otherwise, it is loyalty. The Gallagher Girls display that in spades. 
 Next, there is Zach, the mysterious guy who seemed just like another guy in CMH. Since it seemed like Josh would not be around, I expected Zach to likewise be a one-and-done. Ally really surprised me with that one. I had no idea Zach would be so very central to the arc of the entire series. Zach was always frustrating to me because like Cammie, I had a difficult time figuring him out. Even when I wanted to trust him, to love him wholly, there was always something holding me back. I guess that's a spy for you. I really do have to credit Ally with all the remarkable depth she gave to the story with Zach. You know you've got a well-written character when, despite an inability to trust him and his intentions, you want to trust him. With Zach, I wanted to throttle him just as many times as I wanted him to rip off his shirt. My favorite moments of the series are often the scenes with Cammie and Zach, but not because of the kissing (which, I admit, was spectacular. I mean, there's a scene in UWS that just took my breath away!). It was because Cammie became something more with Zach. She had to be stronger, smarter, more cautious, but she also was more human and she inspired that in Zach as well. Watching them grow together both as a couple and as spies and as people was glorious. 
 The supporting cast was all incredible as well. Cammie's mom, Aunt Abby, Mr. Solomon, Agent Townsend, Mrs. Buckingham, Madame Dabney, Mr. Smith, Courtney Bauer, Tina, etc. These characters never seemed like props. They were real people, and each served a special and distinct purpose. I am sad that like a lot of the supporting characters in Harry Potter, many were not even seen in the final book, but then, by that time, Cammie was past the point of needing so much backup. Still, I will always cherish those initial outings of the sophomore CoveOps class and the gossipy meals in the Grand Hall with all the creme brulee. 
 Finally, the plot. LYKY was so much more a cute contemporary romance than the later books. We got the background, we met many of the players, the stage was set. Little by little, Ally increased the pace with each installment until the books became one high-stakes spy game with romance on the side. I think United We Spy was an appropriate finale. It answered all my questions and gave me the resolution I'd been craving. I don't feel disappointed. I feel complete. I feel like Ally accomplished everything I wanted her to and more while leaving an open enough ending that I know at least some of the Gallagher Girls are moving on in one way or another. I say open because it doesn't spell out the future in precise detail. That said, will Ally go back to this extraordinary spy world? Perhaps. I hope she might, one day, many many years from now. But do I honestly think she will? It's hard to say. The story of Cammie and her friends is almost certainly at an end, and I'm okay with that. But if a character from GG popped up in a future Heist Society or Embassy Row adventure, I'd be okay with that too. 
 I know this was kind of long and ramble-y, but honestly, this wasn't entirely for you. Sorry, guys. This was just what I need for closure for a series that I've been intimately acquainted with for a long, long time. Honestly, I really don't know what I'm going to do. I haven't felt slightly lost like this at the conclusion of a series since I finished Harry Potter. I'm not sure I'll ever have a series where I feel like this again. 
 So Ally, if you read this, thank you. This series has meant so much to me. Thank you for your incredible writing. Thank you for your silly yet totally believable names for gadgets and tactics and fighting moves. Thank you for finally writing a scene in which Zach is wearing a towel and nothing else. Thank you for sharing Cammie and the crew with me, with all of us Gallagher Girls. You crafted a phenomenal tale about a group of girls in spy school who do remarkable things, but for the record, I know the truth. You are the true Gallagher Girl, and you have done the most remarkable thing of all: you made us believe.