Any of these would make great holiday gifts if you're still shopping, or must-reads for 2014!
THE WESTING GAME, by Ellen Raskin
(Thanks @ViolinKnitter for the suggestion!)
A nice in-between MG/YA read! Some details may feel dated by our standards today, but the story, the rich cast of characters, and the awesome young sleuth will never go out of style!
FROM THE MIXED-UP FILES OF MRS. BASIL E. FRANKWEILER, by E.L. Konigsburg
The gold standard for MG art mysteries. Sadly, E.L Konigsburg passed away in April of this year. This classic belongs on every young mystery-lover's shelf!
I AM THE CHEESE, by Robert Cormier
A mysterious family. A haunting tale. A must-read for teens and older MG's.
I KNOW WHAT YOU DID LAST SUMMER, by Lois Duncan
Guys, this books, decades old, is STILL CREEPY. It's been repackaged (as have many of Lois Duncan's other books), and some details have been updated to help modern readers connect.