The Forgotten puts the Animorphs through the ringer, with existential threats and body horror and also more mundane dangers. The plot mechanic is executed well and the ending is suitably dark. This is one of my favorite books in the whole series.

It is part of a shift that has been slowly forming over the last couple of books where they introduce mechanics that can warp reality above and beyond the basic level indicated by morphing technology. The Ellimist and Chee are other examples that get more play, but I like this one a lot.

It really grapples with the burden of leadership, especially since it's easy to forget that the kids are in middle school (approximately ages 12-15) at this point. Jake's storyline grapples with having responsibility beyond his years because he's the leader of the group, and this book gives him a taste of the emotional weight his decisions could have at any point without delving too deep into it.

If you're trying to get a feel for the series as it gets going but don't want to commit to the whole thing, this is a book you could read by itself to get a taste without spoiling major plot points.

The Reaction uses the premise of an allergic reaction to build a nice twist on the usual mission formula. Alienation and being unable/unwilling to open up is a major theme, and we see an extreme example of Rachel's drive to solve everything herself.

I like how the books show you that conversations have happened which readers are not privy to. We first learned the term "nothlit" when Ax was narrating, and now Rachel knows it because at some point Ax must have explained. The reader has already learned it, so we don't need some extra scene where Ax passes the info along. When the books are so short, you really need world-building and implied events like that to ride the line between storytelling and info-dumping. Also little things like how when Rachel is relaying what someone else said she uses words that convey the emotion of what they said, rather than just quoting what happened a few pages/hours ago. If the quotative like had been a thing when these books were written, Rachel would use it all the time.

Wow, the creatures Visser Three morphs are amazing. It's not great for the Animorphs when he's involved, but it's a chance to get snippets of other alien life in the series even if the implications are terrible for the creatures in question.

The Animorphs help some aliens in grave danger. Tobias becomes more active in the team, but has to accept some limitations. The balance of frustration and hope was handled well. When the Animorphs make wishes there's someone listening.

It's difficult to stress enough how much this series leans into the sense that these kids are on their own and can't trust anyone else, that not only does no one else know what they're going through, but that if they tried to explain it would put them in danger. But, with that, it also shows the importance of having people you can count on and can talk to. The Animorphs survive because they are a group who has chosen to work together and trust each other.

I'm appreciating how much each of the kids feels like an outsider even though they are a group. That might sound strange, but it helps to convey the feeling that everyone feels left out sometimes, and while they're sometimes right, it's not really possible to have an entire group who are outsiders from that group. Tobias has felt left out and ineffectual, and he gets an opportunity to fix that but it's a bit of a monkey's paw situation. Not quite that bad, but he definitely doesn't get what he would have wished directly for.

The Hork Bajir-Chronicles tells the origins of the Yeerk invasion, Hork-Bajir as shock troops, and the immediate aftermath of Seerow's Kindness. A slow revelation combines with a sense of inevitability in this exploration of the drive to conquer and the resolve to stay free.

The rotating perspectives give some dimension to the Yeerks as villains, they have reasons for what they do beyond simple cruelty. Because reading the main series tells you where this story will end up, there is a sense of gloom when reading it. It also has some hope, because it is told in a time of new freedom for some Hork-Bajir. The ending is hopeful on a first reading and kind of ominous since I know where things lead after this. It's a pretty good snapshot of the tone of the series as a whole, with Aldrea and Dak as guerrilla fighters instead of the Animorphs.

The Animorphs try to find out what's in Zone 91 and Cassie runs a race. It's a lighter story after the grimdark run of the first 13 books, a chance to breathe.

The Unknown is definitely a pause after a lot of setup and revelations in the start of the series. Most of the major players have been established and things are about to get complicated, but they haven't quite yet.

The Escape is a pool of grief, rage, and helplessness. It's about interrupted grief when loss changes from completely gone back to just out of reach. Discussing humor as a shield and coping mechanism, it describes its role and acknowledges its limits.

Marco is a jokester and a goof when viewed by his fellow Animorphs, but whenever its his turn to narrate his inner monologue is a lot darker than his exterior would project. He's kind of a foil for Rachel, who is outwardly tough but also deeply insecure. To be clear, Marco is also insecure, but he hides it by joking about it and deflecting deep thought away from it. The books engage with this dynamic in a way that feel real.

The Warning shows Jake's increasing sense of internalized pressure as a leader. He's in charge and increasingly isolated. When he almost dies in an insect morph the text takes the time to dwell on his fear and helplessness in a pretty brutal way.

There's some fun stuff with 90's computer tech and chat rooms, but this is not a light book. There's a sense of helplessness, and the crushing reality that no matter how many people they can save, someone is still getting hurt.

Cassie is starting to be more of a lieutenant and confidant to Jake in terms of decision making and ethics. She has been the ethical voice of the team for a while, but this book codifies some parts of their dynamic in a way that feel natural.

These review are spoiler-free, but my stance is that "almost dies in an XXX morph" really isn't a spoiler for this series, since that's a constant in almost every book. You know it's "almost" because there are more books with him on the cover, and morphing is often dangerous. It's mostly used for combat/infiltration, which is dangerous. Even the act of morphing is dangerous due to the possibility of being trapped in morph.

The Underground poses an ethical dilemma related to addiction, and it becomes clear that Cassie's role as the ethical voice is becoming too much. Rachel deals with claustrophobia and Marco laments that none of the great battles involved oatmeal.

Several of the previous books have featured Cassie's role as the voice of morals, reason, and ethics for the Animorphs. In The Underground we start to see that she isn't magically more mature than the rest of them, she's starting to not know what to tell them anymore. They're still kids, probably still in middle school (there hasn't been a direct reference to their level of school in a few books), and nothing is getting easier.

Rachel is the narrator for this one, and this book has a lot of depictions of claustrophobia. I'd have to go back in order to check whether this is a new problem brought on by the events in this book or whether it's been a thread for a while. If it has happened before I think it's been more associated with worrying about not getting out of morph than with being in a small space.

As always, the nightmares are getting worse. Not only are they more frequent, but more of the book is devoted to describing what they are or at least that Rachel is having them.

Wherein Ax discovers that not all traitors are Controllers, and commits to Jake as his Prince. Plus cool Z-space stuff, the Leerans, and cinnamon buns. This series is directly responsible for my love of Cinnabon, as I didn't frequent the mall.

This is a turning point where Ax goes from temporarily aligned with the humans until he can leave, to accepting them as his own. I really love how this is handled, especially since this paradigm shift would take a long time even if little moments can be responsible for large chunks of it. The Z-space theory is great and the snapback effect give a nice sense of urgency to the pacing.

Megamorphs #2 is stuck in a weird bind. It needs to be interesting and impactful, but also to not disrupt the main storyline in case someone misses it. The Animorphs end up in the past due to a Sario Rip and run from dinosaurs.

There's a truly horrifying sequence early on where Tobias and Rachel are inside a stomach being digested, skip that one if you're squeamish. But, really, it's not more gruesome than the main continuity, just more dense because it's a one-off. A lot of scientific details didn't age well in this, so if you only going to skip one you can make it this.

However, it does have an important moment for Cassie, with the theme of ethical dilemmas and moral center than has been developing for the last several books. You don't need to read this one to understand the next book, but it really helps set up the state of mind for Cassie that will contribute to events in book 19 (The Departure).