So, I want this guy's career.
He graduated from both Harvard and the Iowa Writer's Workshop. He's won the Pen/Hemingway award and the Stephen Crane Award.
But basically I want his career because it goes something like this: Write a first book (collection of connected short stories) and win prizes and awards. Write a second novel that is critically appreciated, if not a blockbuster. Write a third novel and have a super-mega bestseller that is very, very well written. I am a fan.
In this video, Cronin talks about his inspiration/motivation for writing The Passage, which is interesting enough, but he also talks about his characters. Before he can write them, apparently, he has to know "what they're not telling." It's one of those statements that I know as a writer to be true, but I didn't think about it until someone put it in just the right way.
How I interpret Cronin's message: You have to know your character's secrets, their shames, and dirty little desires. Does this mean that every character has to have killed someone in their past? No, though The Passage is a thriller/horror type novel so don't be surprised if that's the case for a character or two. Rather, the 'what they're not telling' idea adds tension where there might not have been any before.
Take, for example, the nun in The Passage (Sister Lacey). (I'm not really giving anything away, you learn all this the first or second time you meet her.) She's from Sierra Leone and she was raped, almost killed by a group of mercenary/soldier types. She can see the future, but she doesn't talk about it. The reader knows it, understands it, but the other characters do not. There are several scenes that hinge on Sister Lacey's knowledge and what she's willing to do because of her experiences.
Imagine if Sister Lacey was just a nice nun, doing nice nun things. She's charitable and nice and does what she's supposed to without any kind of secret or struggle. Say it with me: Boring!
Note that the reader also knows the secret...it doesn't stay hidden from them forever. If the reader is left in the dark, then there is no tension. All they see is mopey characters, or characters acting in ways that do not make sense. To engage the reader, we need to focus on letting them know enough to cheer the main characters on.