If it isn't clear that in order to work with director Christopher Nolan, it's who you know, you need to look no further than next month's "The Prestige," a movie that stars Christian Bale and Michael Caine, two people who "coincidentally" also starred in another Nolan project: "Batman Begins."

When it comes to that movie's sequel, "The Dark Knight," Nolan is keeping it close to home once again, hiring his brother Jonah to pen the screenplay.

Christopher Nolan told Creative Screenwriting magazine that he and "Batman Begins" co-screenwriter David Goyer were off directing other projects (Goyer for "The Invisible" and Nolan for "The Prestige"), and someone had to break the story.

"Jonah seemed the most obvious choice for someone to crack on the script and see if our story held any water," said Christopher Nolan, according to transcripts from IGN Filmforce. "You sit there with your cue cards, but 'till you have to write a screenplay, you never actually know what you've got. So we pulled the pin and tossed the grenade."

Jonah Nolan said it was his brother who turned him on to Batman in the first place, especially the version best known by Frank Miller that was translated into the most recent movie.

Filming is expected to begin soon for "The Dark Knight," which is scheduled for a 2008 release. Heath Ledger has reportedly been tapped for the role of The Joker.