Librarians. Secret societies. Books. Spies. Adventure. Alternate universes. Vampires and werewolves. Victorian London. Dragons. Time Traveling. 
 All of these things separately are things I love and the thought of combining them is a bit nerve-racking. After all, there are so many elements and none of them really related that something, somewhere will get lost, but that doesn't happen with the Invisible Library. The Invisible Library tackles the tough task of combining these elements into a book that is not only a delightful read, but probably one of my favorites for the year. 
 The Invisible Library tells the story of a secret society of librarians that have committed themselves to 'The Library'. Upon becoming an agent of The Library, or essentially a Librarian, these individuals vow to work on missions that involve heading to alternate realities (some of which are considered 'chaos filled' which means that magic and reality combine to create a chaotic situation) and retrieving rare/unique copies of books. Unfortunately, retrieving these rare books isn't always an easy task. 
 The Invisible Library follows the story of Irene, a young professional spy/agent for The Library. She - along with a novice by the name of Kai - are given the task of retrieving a rare book from an alternate London that has vampires, werewolves, Fae, and advanced steampunk like inventions. The task seems easy enough, until they get to the new universe and discover that they are not the only people looking for the book and one of those people is a man that was thought to be an urban legend amongst The Librarians. 
 Kai and Irene spend most of the book looking for clues and trying to sort out who has the book, who is an ally, who is an enemy, and what is going on political wise with The Library. They also trying to solve a mystery, find the book, beat a "bad guy", and learn more about each other. 
 I absolutely loved The Invisible Library. It is pretty much everything I look for in a book. It has action, adventure, mystery, and books - lots and lots of books. Even though The Invisible Library is a favorite of mine and I enjoyed it, it is far from a perfect book. I'll highlight some of my favorite aspects of the book and talk about some of the aspects that didn't really work for me. 
 A huge highlight of The Invisible Library is the way Genevieve Cogman weaves so many seemingly unique concepts into one coherent story. There are a lot of elements that could come across as disjointed or random, but it all comes together nicely. 
 Another aspect I found enjoyable was the way Genevieve Cogman was able to take a familiar world and give it a unique twist. Everyone knows what Victorian London is/was like, but the Victorian London we were introduced to in the book was new and unique. It felt different, which is what added to the excitement of the book. 
 One of the things I found a bit frustrating about The Invisible Library was some of the seemed felt awkward or a bit out of character. The scene that comes to mind is within the first 25% of the book when Kai and Irene are forced to spend a night together in a hotel that resides in their alternate London. Kai mysterious, and what feels a bit out of character, starts throwing himself at Irene. He asks if she wants to sleep with him and feels hurt when she rejects it. 
 Previously, there had been no indication that Kai had any romantic feelings for Irene. The two had just met a few short hours before. It just seemed out of place. 
 Another aspect of The Invisible Library that felt awkward was the way the world was introduced. Instead of going for a complete info dump that involved explaining how The Library worked, how alternate universes worked, the role of the Librarians and supernatural creatures, and who the bad guys were, Genevieve Cogman goes for a more 'learn while you read approach'. 
 The learn while you read approach is great, as it speeds up the book. You aren't bogged down by lengthy descriptive paragraphs, but it sometimes makes you feel like you missed something. There were times when I was like 'who is this' or 'what is this', only to discover that we hadn't learned about it yet and would learn the answer to that question several chapters later. 
 I will admit that The Invisible Library isn't overly complex. It isn't overly simple either, but if you are looking for something extremely detailed, it probably wouldn't be this book. The main focus of the book isn't in creating overly detailed characters, but in the world building and adventure. The characters develop throughout the book, but it is clear that isn't the main focus of the book. 
 Even though The Invisible Library isn't a perfect book, it is an enjoyable one. Immediately upon finishing it I had two things in mind. First, I wanted to become a Librarian. I mean who wouldn't want to be a time traveling spy who is on a mission to save rare books. Second, I couldn't wait for the second book. 
 Overall, The Invisible Library is a fun easy read. While the main plot might - to some - seem predicable, the unique world building and action more than make up for it. This is a definite must read for any book lover.