The Magic Ex Libris trilogy about librarians who can do magic with books concludes with this book, and it's a solid finish! I really enjoyed the premise built around a love of reading and geek fun, especially when it could have gone a completely silly route with adventures solved by clever use of books, but Hines took a more serious approach instead. I appreciate the flawed magic system in this book, flawed because it's created by flawed people and because there is no way to please everyone. The Porters are not the good guys, necessarily, though they may try to be the closest thing. Hines explores interesting issues and asks a lot of "what if's" with this series.
Book 2 ended on a grim note, with Isaac losing his magic and being kicked out of the Porters, Jeneta being possessed by a thousand year old ghost with a god complex, and the Porters in disarray, so there's quite a lot to address going into book 3. Hines handled Isaac's character well, especially dealing with depression and not having magic to use without feeling too drawn out or belittled. I have to admire how Isaac's character is resourceful and clever, and having magical abilities enhanced what he could do. Even without magic and any support from the Porters, Isaac relies on his research skills, knowledge, resources, and his contacts, and he gets pretty far with his search for Jeneta and finding a way to stop Meridiana. It's a nice balance between how his magic defines him, yet he is still someone without magic who can make a difference.
The action moves pretty fast. Just like there is not too much wallowing and dragging out Isaac's depression, the events move quickly from one event to the next. Things get quite bad for Isaac, and the ending does not resolve or address everything that's happened to Isaac, it does leave with a hopeful note that things are not over and are in process of getting fixed. It almost felt like there were too many twists and turns without much time to take it in, leading to some huge changes. Maybe that's life there, though I do appreciate the story was taken seriously, dealing with matters in a meaningful way instead of just glossing them over: the Porters' questionable procedures and methods, the way "normal" people would react to the existence of magic, and how people deal with tragedy. Isaac has to live with the aftermath of the events from book 2, and the "normal" people he know no longer trust him. Hines gives a sense of how people would respond if magic existed with snippets and excerpts of news, articles, letters, and reports with each chapter, and they are humorous sometimes, but they sound like something plausible. It's not just "what if this kind of magic existed and how cool would that be" but "what if this kind of magic existed and what would that mean for the world." It's a more long range look at the "what if." The Porters were never quite the good guys, though they were a temporary hold on larger problems. They are a flawed institution, but this demonstrates more complexity than if they were simply and unquestionably good guys who know what they're doing.
I liked that Juan Ponce de Leon was a little move involved, though I thought book 1 revealed that he was banished with a magic geas that would prevent him physically from coming to the US (that's why he couldn't help with finding Gutenberg). He shows up, with no mention of his banishment or geas, though later on he avoids letting the Porters know he's there. Both he and Gutenberg add perspective, being longer-lived than their fellow humans and seeing things in the long term better, but, even better, they both have different approaches to the current problems and still don't agree on what to do. It adds to the sense that the world is complex and there is no one way to solve their problems. I enjoyed how their interactions were understated and hinted at their past relationship, so there was some tension and sense that there was still something between them, but it was not the angst found in teen books or romances.
As much as I enjoyed how Hines introduced and explored the "what if's", it felt like Meridiana as the villain was the weakest point of the story. It's the problem with ultimate supervillains--it's just one person who has to be beat. The first 2 books hinted at some larger, underlying threat that the Porters have been trying to hold back and even Gutenberg feared. The whole worldbuilding was great, but the final conflict was about defeating a thousand year old megalomaniac wannabe goddess, though it was clever how it was resolved. The ending does leave some loose ends and cleaning up, maybe hint that it's going to be an ongoing and imperfect process, but I kind of wished there had been more to Meridiana's threat.