The Hound of Rowan

I liked this book written by Henry Neff. Max is sitting next to his dad on a train to Chicago when he spies a man staring at him with one green eye and one eye as white and dead as stone. The train goes black when it enters a tunnel, and the man disappears without a trace. But Max's strange day has only begun. Hours later he happens upon a mysterious Celtic tapestry at an art museum – all the more intriguing because the tapestry hangs in a room that doesn't seem to exist. Max's life then takes a further turn for the bizarre when on his return home he is contacted by a Recruiter who wants to whisk him away to the fantastical Rowan Academy.

This is the first book in the Tapestry series. The author also illustrates the books.