Gone Girl, and then her second book, Dark Places. Most recently, I finished her debut novel, Sharp Objects.
Sharp Objects follows a journalist named Camille Preaker. After a history of self-harm, she has marginally put her life back on track... until her editor sends her back to her home town to cover the investigation of a serial child murderer. Contact with an overbearing mother and a rebellious younger half-sister, combined with the grisly murders themselves, begins to unravel her precariously balanced normalcy.
Gillian Flynn certainly has a recipe for her books. She's almost a female Chuck Palahniuk, writing about messed up protagonists with dark back stories. And while she proves a decent writer even here in her first effort, you can definitely see that this is a recipe that had to be improved before she arrived at Gone Girl. Dark Places was not as polished, and Sharp Objects is yet another step back, rougher around the edges.
Flynn is at her best in portraying her central character. You're always inside her head, and it always feels natural. If you're lucky, you don't know anyone like Camille, but the protagonist still feels like a real person. Not "relatable," entirely (as she isn't meant to be), but real.
Where Flynn stumbles a bit is in the unveiling of her mystery. With a murderer at the core of the plot, "whodunnit?" is of course the natural question to ask. And much of what's going on isn't hard to suss out long before Camille does. There's a bit of a turn thrown in near the end, as though Flynn recognized a need to complicate the story a bit, but it doesn't unfold as naturally as the main character's own tortured thoughts.
Overall, I'd give Sharp Objects a B-. If you've read Gone Girl and/or Dark Places and enjoyed them, you'll probably find this a pleasant but mild diversion. But this isn't the book to sell you on Gillian Flynn if you haven't read her before.