While I always felt the Who/What/Which bit was a bit cute, the rest of AWiT remains timeless to me in a way that so much of the SF/F of my youth does not.
In particular, the vivid imagery of Uber-Conformity on Camazotz (bounce, bounce, bounce) is etched irrevocably in my brain.
Ms L'Engle wrote some other fine work, but this one in particular is still stunningly powerful.
How ‘A Wrinkle in Time’ Changed Sci-Fi Forever
Madeleine L’Engle’s time-hopping heroine transported sci-fi into a new dimension.
I find Robert A. Heinlein's YA books eminently re-readable. More so than much of his adult fare.
+Scott Randel I tend to find the science errors a bit too distracting.