Note: please do not send a carrier pigeon.
He is happy to answer any questions you might have about something he’s written, via the social media outlets mentioned above.
That said, while he’s happy to answer any questions you might have about something he’s written, he cannot read your fan-fiction, unpublished novel or short story. He also won’t give you writing advice, put you in touch with his editor or introduce you to another author. Beyond that, go nuts.
If you’re looking to get in touch regarding rights enquiries, offers of work, or some other professional capacity, feel free to contact him via any of the methods above.