This is a re-read. Most of the people I grew up with read this when we were kids.
Reaction when I was a kid: This book is AWESOME! And FUNNY! And there are so many neat concepts that I'd never thought of! And wordplay I'd never heard!
Reaction now: Well, now some of what I thought was terribly clever when I was a kid seems a little simple and obvious, but it's still a very good read. And I hope that Z has the same reaction to it on her first read that I did. Because this book is all about loving knowledge and being able to put it into practice. And it's also about having fun with language.
Age I'd let Z read it: 7