I think it must've been around second grade, but I'm honestly not sure. We had a relatively awful AIG teacher. She pretty much just made us read novel studies, which I detested. I didn't like being told what to read and how fast to read it; I read quickly, unusually so. It took me a week to read the third Harry Potter book by myself, in first grade. I don't remember how long the fourth took -- probably two weeks or so. The fifth must've been similar. I finished the sixth in a day.
Anyway, The Green Book was one such novel study. It was unlike anything I'd ever read before.
Father said, "We can take very little with us"...
It's not a long book. Looking it up, it was 74 pages. The print was decently large, and some of the technology that was familiar to the original 1980s audience seemed pretty alien to elementary school students in the early 2000s. (Slide projectors? What're those? Are those like overhead projectors? LCD projectors weren't a thing yet.)
It was very strange, though. In the first few pages, the characters boarded some kind of ship and left Earth. I don't think anyone ever said it was a space ship. That was one of the big leaps of imagination we were expected to make. The passengers were fleeing some earthly Disaster, the nature of which the young protagonist didn't seem to understand.
As an elementary school student in the early 2000s... we did know all about that. There'd been a Disaster a few years previously, and lots of people were dead, and lots of people were angry, or scared, and there were terrible wars going on in places with funny names and it was a lot harder to fly on an airplane all of a sudden. We were pretty good at not quite knowing about Disasters while still being aware of how awful they could be.
In that way, I still relate to the young protagonist. She had little memory of Earth, or of any world before the Disaster. I do not remember 9/11.
But I digress.
It was the first book I'd ever read that made me think about what it would be like to live on a world beyond Earth. In retrospect, it makes me think even more. The colonists had euthanasia pills to take if Shine, the planet upon which they landed, turned out to be inhospitable for human life. They never quite said what the pills were supposed to do, but it was heavily implied -- if they didn't take the pills, they'd be the only ones left. The solemn scene with the Father and his children around the table, hopeless and not understanding, with the bottle of pills. The pure relief when they found a way to eat the crystalline wheat that grew in the planet's soil.
The world was four years away. It doesn't specify how fast they were traveling -- very little is said about the ship, only that its computers weren't very good and it had a "gravity machine". But we can take some guesses, in part because there's only one world that has a reasonable chance of being habitable within that distance: Proxima b.
We didn't know about Proxima b when the book was written.
We haven't 100% confirmed it now.
But it's probably terrestrial, probably habitable, definitely the closest planet to our solar system if it exists.
That wasn't the point of the book, the point was to talk about what's really valuable in life and how children can actually be incredibly wise and/or the only keys to the future. Which, okay, fine. But that isn't really what's stuck with me.
(The question "if you could only take one book with you -- and the planet was going to be destroyed, ONE BOOK ONLY" is now laughable, we KNOW how little computer memory a book takes up, but it is still an interesting question. I might be inclined to take Arabian Nights or some such compendium.)
What stuck with me was this notion that books could be about things that aren't real yet. Fantastic things, wonderful things. Books didn't have to be about real-ish people doing real-ish things (like cutting class to listen to baseball, or going to school, or magic -- I firmly believed in magic).
Books could leave Earth behind.