Last time I went, someone brought in the opening for a book they were working on. Before reading, they described it as an intricate sci-fi story, bridging religion and science, centered around an autistic man discovering a way to bridge the regular world with another dimension. The later parts of the book would be about trying to find a way to put the genie back in the bottle once it was released.
Sounds like an incredible story, huh?
Then they started reading.
The first chapter is about his girlfriend and her musings on how much she wants to leave him, but can't bring herself to.
When asked about the difference, they replied that they had read that romance novels were the biggest seller of books on Amazon, and they wanted to grab those readers.
Now, I want to point out that is a recognized fact. Romance novels ARE the biggest sellers on Amazon and probably most other outlets as well. It's also something that you want to portray your work as cross-genre, in order to attract readers that otherwise might pass on your book.
That being said, you want to be very careful when you set up a bait-and-switch like this. Yes, you might draw in a few people that wouldn't have read and enjoyed your work before; but you also run the risk of pissing off just as many, if not more people.
Given the description of the book, if you picked it up expecting an interesting sci-fi story and found the entire first chapter read like something out of a romance novel would you really keep on reading? Or would you close the book and move on, possibly leaving a scathing review on the way past?
What if you read the first chapter and thought you were picking up some kind of romance novel? Once the first chapter is over, the POV switches, and the focus is entirely on the guy and his discovery, would you keep reading? Or would you be outraged at being caught in the bait-and-switch?
I actually know from experience that people get angry when they don't get what they think they bought. Angry people are also those most likely to leave bad reviews.
My first book was supposed to be a slow horror/thriller story. Unfortunately, between the cover, blurb, and the way it was written, a lot of people seem to have mistaken it for a supernatural romance and I paid the price for that in reviews. That's one of the reasons that I withdrew it from sale. It was completely unintentional, but it did end up being a kind of bait-and-switch. Some people did like it, despite it not being what they thought it was, but far more were angry.
Yeah, not exactly genre-specific, is it?
I'm only speaking from my own experience. I'm not saying anyone should or shouldn't try the bait-and-switch approach. If you know how to advertise to specific groups, and you're aware of the risks involved, feel free to give it a go. After all, what doesn't work for some, might work very well for others.
Just make sure you're well aware of what you might be bringing down on yourself should you get it wrong.