4/16/23: Update--Three volumes of this series have been banned by Vero Beach High School because they are afraid it might encourage students to kill their teachers, something it has yet to successfully do after millions of readers have read it. The ultimate point of the book is that this teacher encourages his struggling low-level classroom to believe in themselves.
Original review, 2/21/16: Crazy premise: A goofy-looking smiley-faced monster has already destroyed much of the moon, and now threatens to destroy Earth, in one year, but he also wants to become a teacher. For some reason. And he's a good teacher, too. Koro Sensei, they call him. The unkillable teacher.
So, he makes it clear that his low-performing students, in order to prevent the unthinkable, must assassinate him, of course, and he is aware of this. He encourages them to work on this group project, using all of their analytical and creative skills, learning to work together, to try and save the planet. And he is--so far, at the conclusion of this volume--unkillable, though they seem to be making progress in their goal, getting more inventive as they proceed.
Given the gun violence in US classrooms, this premise would appear to be unthinkable, but somehow Matsui makes everyone pleasant and the plot amusing. There's a range of students you come to like, with varying abilities and strengths as students and. . . assassinators. But I emphasize: This series is comedy, not a guide to classroom violence; it was wildly popular first in Japan, and then in anime, and now across the world.
Crazy, crazy stuff, so obviously you have to read it. You will be smiling like this happy-faced Koro Sensei, this seemingly unkillable teacher, who has an ulterior motive to nurture these young kids. And yeah, they love him. It's pretty funny stuff!