The Tripods

My top three would be: Dune by Frank Herbert (only the first book, dislike the rest of the series) Farmer in the Sky by Robert Heinlein The Crysalids by John Wyndham I've probably read these three books at least twice a decade since the 80s when I was a teenager. The Complete Robot from Isaac Asimov would be a close forth. The Tripod Trilogy by John Christopher would be fifth on the list. Hadn't read since a teenager, but about ten years ago tracked down copies of them (and the prequel) and it was delightful to reread.

Many of the already mentionned books. Hal Clement's Mission of Gravity, in the hard science genre. As a kid I was absolutely stunned by The Tripods. I highly recommend these books (trilogy) for your kids (10-13 yo).