Other books for a 10 year old:
My kid enjoyed Alcatraz Versus the Evil Librarians,
and the next couple books after that (about the 4th? book they went downhill), by Brandon Sanderson. With a librarian in the family, maybe they'd be amusing. I will add that with the first book (the only one I read), I was pleasantly surprised to realize towards the end was NOT just goofy, disconnected humor, but things had actually been building up and clues had been scattered along the way and it was actually clever!
I second Watership Down, mentioned by others.
I'd second Ender's Game as others have mentioned; I think it's fine for kids. But I have reservations about some of the other Ender books -- it'd be a book-by-book question. I recall domestic abuse and just an icky family situation, and grotesque killings, in Speaker for the Dead.
Jules Verne -- The Mysterious Island, in particular, is fun.
Runemarks, Joanne Harris
The Prophecy, Hilari Bell
Powerless, Matthew Cody
Heart of a Samurai, Margi Preuss -- based on fascinating real-life person
The Ghost in the Tokaido Inn (mystery series start, set in 18th century Japan), Dorothy and Thomas Hoobler
Happy Kid, Gail Gautier
a time-travel trilogy by Maiya Williams, starting with The Golden Hour -- first set in French Revolution time, 2nd in Cleopatra's time, 3rd in Gold Rush
