"What is the theme of your book?"
Cue deer in headlights look.
The reason I hate this question so damned much is not because my books have no theme, but because they have many, and what someone could or would take away from the book really does depend on the person reading it and what life experiences they're bring to the reading.
In my unpublished military sci fi, Skylark, for example, a reader might latch onto the relationship between the titular character, Commander Bennejin Skye, and the woman he loves. For them, the theme of the book might be love gives us strength.
Which, I mean, yeah. That's definitely in the book, and not just between Skye and his love interest, but between Skye and the other members of his team.
Another reader, though, might look at the integration of aliens into Earth's pan-world space militia and see an allegory to race relations. It might occur to them that, in fact, these aliens are so much like us that they're pretty much indistinguishable and the prejudice against them is stupid. They might look at the fact that humanity would be utterly lost without the alien aid, and find that the theme of the book is stronger united.
Which, yeah. That's definitely in the book.
Someone else again might look to Skye himself, and all that the commander did; and all that he endured doing it. They might take in the losses and the hits and decide that the theme of this story is that heroism is hard. Or, to put it in more Harry Potter-esque terms we must choose between what is right and what is easy.
That wouldn't be wrong. It's certainly in the story.
Others might look to Commander Skye, and see this clever, broken man and find that the theme of the book is that a hero does not need to be perfect. That it's possible to be a hero even if you aren't all shiny and confident with an unshakeable moral centre. A hero can be uncertain, and angry, and a little bit of a cheeky bugger with authority issues.
And again, they wouldn't be wrong.
So, which of these should I respond with when someone asks me that god-awful question?
"What is the theme of your book?"
"Here are four. Take your pick."
There are would-be writers who love to try and stump authors with that very question, as if it is all that matters about a story. I've had it more than once. The question in and of itself wasn't really an issue. The smirks that accompanied them was too much, though.
It is my firm opinion that the theme of the book isn't nearly as important as people are making it out to be. What matters is a good story, with depth and heart, and believable characters that are well-written.
I think starting out with a theme isn't the best way to work on a story. Trying to cram story elements and character actions into a neat theme box tends to stifle the writing, making characters behave out of character just to fit, and creates plot points that feel and read horribly contrived.
That's not to say that themes don't matter, they do, but I don't think they're nearly as important as people make them out to be, and it's a stupid question to ask an author. It's a brilliant question to ask a reader, though.
Writing, like any art, should be up to the viewer to interpret.
What is the theme of my book? Read it, and tell me.