The first two books in this series, My Teacher is an Alien
and My Teacher Fried My Brains
, follow the same basic plot. A kid finds out that her (Susan)/his (Duncan) teacher is a really an alien, and it's up to the kid, with (in the first book) or without (in the second) help from others, to try to expose the alien for what he/she really is. There's a lot of suspense, as there's a time limit before this needs to be done, and getting proof is both dangerous and difficult. They're both great suspenseful adventures set in a local setting.
Until The Reveal
. The aliens, you see, were actually not evil at all, but were planning to use the kids as proof that humanity could be redeemed, and try to save Earth from destruction at the hands of other aliens who view Earth as a threat. Once we discover that, the kids go on a trek through the universe with the aliens and the series essentially turns into Star Trek
with social commentary thrown in. Social commentary like why is there so much suffering on Earth, why do governments in third world countries oppress their own people, those kinds of questions. That's interspersed between what's essentially little more than Life On A Spaceship, as the kids meet different aliens, encounter different cultures, and have stuff happen during their trip. Like I said, Star Trek
That's precisely what I don't like about Bruce Coville
. A lot of his books seem like him trying to show off how funky and outrageous his character designs, worlds and cultures can be. Here's a machine that creates food based on what you program into it! Here's an alien who's divided into pieces that have to be beamed up, piece by piece, in order to transport him from place to place! It's definitely imaginative, and many of his books make use of his ideas and use them well within the plot, but it just ain't my thing.
Frankly, the My Teacher Is An Alien
series is two different genres. If you want exciting suspense and a looming threat within the school, read the first two books. If you want Star Trek
with moral lessons and Bruce trying to show off how weird his aliens can be, check out the last two. It's possible to enjoy all four, but they are radically different experiences.