How old is Boo Radley? I'm writing a creative essay about him and I'd like to include his age... Do you know? Thanks in advance

I don't think it ever says how old he is in the book, nor is there any indication in any of the booknotes sites (e.g., http://www.sparknotes.com/lit/mocking/characters.html )

I'd say he is in his late 20s or early 30s. That's my guess, based on his actions.

=)