The first chapter of "The Passage" is the story of the birth and early childhood of Amy, a character who ultimately becomes the central MacGuffin of the book. You can read first 40 pages of the book using Amazon's "look inside" feature. The opening tells us how Amy's mother, a diner waitress named Jeanette, conceived her baby during an affair with a flashy salesman who was passing through town.
The book begins with Jeanette getting pregnant and having the baby. Then her good-natured father dies. The lover returns and begins an abusive relationship with Jeanette, but she ultimately kicks him out. She struggles to make ends meet but loses her job and her home and fragile foothold on lower middle-class status. Jeanette sinks into poverty and prostitution. Six year-old Amy winds up sleeping in the bathroom at a seedy motel, while Jeanette has sex for money. Then Jeanette shoots a john who tries to rape her, ditches Amy at a convent and walks out of the story.
This takes fifteen dense pages, and I can't see the point of it. Jeanette seems entirely unnecessary. If the book began with her walking into the convent and leaving the child, with no explanation of her history or rationale, "The Passage" would be no worse off for the omission of the rest of this background information.
Maybe the Jeanette chapter has something to do with the conceit that this is a quasi-religious text; the telling of Amy's ancestry is, perhaps, intended to resemble the Biblical genealogies. But the Bible device isn't a uniform structural element throughout the story. While "found materials," diaries and letters created by some of the characters, are interspersed throughout the book, large chunks of the narrative are also written from the viewpoints of characters who die without recording their thoughts.
It's also possible that Jeanette's sad story is an indictment of the world as it exists just before everybody gets eaten by vampires. Maybe the cruelty and callousness of the society that uses and consumes and discards Jeanette is meant to be analogous to the vampire's hunger. But if Jeanette is that kind of metaphor, it's a clumsy, preachy way to start the book.
I think Jeanette is not the beginning of the story or part of the story at all. This opening chapter doesn't set any conflicts in place that continue, and it barely introduces any characters who will play a role in the story. We meet Lacey the nun who will be important later, but getting her in isn't really the focus of the chapter. We learn nothing of use about Amy. I think Cronin spends this first five-thousand words or so grinding his gears, spinning his wheels, establishing extraneous back story, and doing all the things writers should not be doing in the first chapter of a novel.
There must be a reason Cronin started where he started. He's a smart guy and a good writer; he must have looked at this chapter hundreds of times, and he must have a reason for starting here. He evidently spent years working on this book, and I'm sure a lot of thought went into where to break into the story. But I've got no idea what the rationale for this chapter might be. To me, it feels like a mistake or a miscalculation.
I guess the standard disclaimer is that Cronin gets away with this because he is uncommonly good at writing and at telling stories, but I bet some percentage of his potential readers won't get past the slow start and into the meat of the story. Not that it's hurting sales much; "The Passage" has gone viral.