Not much is yet known about the film, other than that its screenplay is by Gregg Hurwitz, who was involved in the most recent V series and has Orphan X at the option stage with Bradley Cooper (Silver Linings Playbook). He is also a published author who has written comics for Marvel (Wolverine) and DC Comics (Batman), but The Book Of Henry is an original script. Which means there is no source to plunder for details.
It's clearly been around for some time, however, since Trevorrow says, "Book Of Henry is a remarkable piece of screenwriting that has stuck with me for years. I feel very fortunate to be able to tell this story. It is a true original."
Shooting is pencilled in for September in New York, so we should expect casting news sometime soon. Jurassic World, meanwhile, is out on 12 June.