With The Girl on the Train, British author Paula Hawkins has written one of those books with a plot so delicious, you wonder why you didn’t think of it yourself.

Rachel Watson takes a commuter train from her slightly grubby suburb into London every day. It used to be to get to work. After she gets fired for drinking on the job, Rachel still takes the train so her roommate won’t know just how far she has fallen.

Often on those train rides, Rachel catches a glimpse of a couple sitting on their back terrace, a “perfect, golden couple” whom she names Jason and Jess. She is sure they are blissfully happy, just as she used to be when married to Tom, before he cheated on her (which she found out about by reading his email, “the modern-day lipstick on the collar”).

Rachel is an exasperating mess, and she makes for a wonderfully unreliable narrator. She drinks on the train—a little Chenin Blanc, or gin and tonic in a can. She calls Tom late at night when she’s blackout drunk, annoying his new wife and waking up their baby. She builds a whole story around Jason and Jess based on her view from the train, imbuing in them all the things she misses about her own marriage. So it’s no wonder she’s outraged when, on one sunny morning, she sees Jess kissing another man in her garden.

“I am furious, nails digging into my palms, tears stinging my eyes,” Rachel says. “I feel a flash of intense anger. I feel as though something has been taken away from me. How could she? How could Jess do this? What is wrong with her? Look at the life they have, look at how beautiful it is! I have never understood how people can blithely disregard the damage they do by following their hearts.”

Rachel only learns that her Jason and Jess are actually Scott and Megan Hipwell when Megan goes missing. When Rachel realizes she was in their neighborhood the night Megan disappeared, she frantically tries to retrace her drunken steps and finds herself drawn into Scott’s life and, in the strangest of ways, her own past.

The Girl on the Train is the kind of slippery, thrilling read that only comes around every few years (see Gone Girl). Hawkins, a former financial journalist, has written a couple of other books under a pseudonym, but this is her first crime novel.

“[My books] got sort of darker and darker, and the characters got more complex,” Hawkins says by phone from her London home. “I’ve always read crime fiction, and it’s always been in my head as something I wanted to do.”

The voyeuristic roots of The Girl on the Train came from Hawkins’ own commuting days.

“I used to commute when I was a journalist, from the edges of London,” she says. “I loved looking into people’s houses. The train went really close by apartments, so you could see in. I never saw anything shocking, but I wondered, if you saw anything out of the ordinary, an act of violence, who would you tell and would anyone believe you? I had a germ of it in my brain for ages. The voyeuristic aspects of commuting, everyone has. Even if you commute by car, you look into other cars.”

In Rachel, Hawkins has created a complex, heartbreaking character whose penchant for self-sabotage is breathtaking. She’s lost everything that mattered to her and can’t quite find a way forward.

Like 'Gone Girl,' Hawkins’ novel hinges on a late-in-the-game twist, and this one is a doozy. As you might expect, this sleight of hand is not easy to pull off.

“I feel more affection than most people will toward her,” Hawkins admits. “She was living this normal life and then had this incredibly rapid fall from grace. She’s obviously gotten herself into a mess with the drinking. She’s teetering on the edge, but could get back on track. I understand she’s a really frustrating character. You just want to shake her and say snap out of it.”

Like Gone Girl, Hawkins’ novel hinges on a late-in-the-game twist, and this one is a doozy. As you might expect, this sleight of hand is not easy to pull off.

“It’s a really tricky thing to do, actually,” Hawkins says. “It’s all about feeding tiny pieces of information, but hopefully keeping them slightly ambivalent. You have to have different people see different things in different ways, and hold back particular pieces of information.”

Her book has been optioned for film by DreamWorks, something that Hawkins is trying to take in stride.

“It’s very exciting, yet I’m trying to not be too excited,” she says. “These things take a really long time. It could be years, it may not happen. It feels unreal. I haven’t cast Rachel. Possibly because she’s not beautiful, and it’s impossible to find not-beautiful actors.”

(She has pondered Michelle Williams as Megan, with her “slightly dreamy, lovely blond prettiness.”)

A longtime London resident, Hawkins wrote about financial issues for a variety of publications for 15 years. She’s lived in Paris, Oxford and Brussels, and was born and raised in Zimbabwe.

“My parents still live there, actually,” she says. “It was a very lovely upbringing. When I was a child, it was a white-only government, effectively an apartheid system, although they didn’t call it that. As a 5-year-old, it didn’t really hit home. It was a nice place for me to grow up, but I am aware that the pleasantness of my childhood was bought at a high price.”

Now a full-time novelist, Hawkins is working on a follow-up while awaiting whatever comes her way with the hotly anticipated release of The Girl on the Train.

This article was originally published in the January 2015 issue of BookPage. Download the entire issue for the Kindle or Nook.