One of my first introductions to science fiction, Shape-Changer shaped my love of the genre and of reading in general. It's been a while since I read it, but I remember how captivated my second grade imagination was by the story.
Awesome things about this book:
1) A young, male protagonist and a female deuteragonist. Boy characters were awesome because I was a boy and I could relate. Girl characters were awesome because girls were this enigmatic curiosity. They were like me: fun-loving, adventurous, and strong. But they were different, too, in ways that I couldn't put into words but that captured my imagination with satisfying whimsicality. (I think they still kind of do that.) I love stories that capture the magnificent differences between the sexes and the beauty that comes from putting boy and girl friends together on a journey. It's like, what's better than Gushers and Fruit Roll-ups? Gushers and Fruit Roll-ups AT THE SAME TIME! And, yeah, that's probably a little deep for a review of a grade-school book, but the elements of characterization were there, and ever since, I've gravitated toward similar pairings in stories. Elfangor and Loren in Animorphs. Luke and Mara Jade in Star Wars. Am I the only one who knows those references? Man, I must be a nerd.
2) Tension! This was probably the first book I read where the good guys were clearly in danger of death by evil alien. The pacing and portrayal of conflict drive the story well for the target audience.
3) Bonus: This book was where I learned how glass is formed. Cool, right?
If you're familiar with sci-fi books and literature for young readers, this story might be a dime a dozen. But it was the first of its kind I came across, and that makes it an instant classic for me! I'd wager young readers today would find it just as exciting and fun as I did 20 years ago. (I can't believe I'm old enough to say that.)