As an author, I have no say about my covers (well, beyond the usual pleading, begging, and generally undignified behaviour that I will spare you all), and none on the cover blurb; I have no say about what goes on the spine, and in the end, no say about where the book is actually shelved in the stores.
But as a reader, I know roughly what I want to read on any given day (the exception to this is Terry Pratchett, who I can read in any mood, at any time, and in any sleep-deprived state) and I tend to pick up a book according to that amorphous desire. And boy, if I pick up what I think is a Robin McKinley novel, and I end up with a Horror novel or a Military SF novel, I'm likely to be peeved beyond reason at the book I did get. Even when the book itself, as written, is entirely blameless.
Nothing new here.
But… wait, I'll get to the relevant part.
I write under two names (well, or three, if you count the Sagara West amalgamation): Michelle West (largely for DAW) and Michelle Sagara (for Luna); my first four novels, written as Michelle Sagara, have been reprinted by BenBella books under the name "Michelle Sagara West".
The West novels are all interconnected; they all take place in the same world, and are actually all on the same time-line. I am not the master of incluing, and my guess is that it's pretty hard to read any of those books without reading the ones that preceded them. They are all multiple viewpoint books, and while I would now structure the first 2 novels of the SUN SWORD series differently, the disparate plot threads and character arcs take some time to come together. Where time in this case means thousands of pages. Literally.
I try to end each novel with the closure of the novel's sub-arc, and with some sense of the emotional resonance relevant to that novel – but the story isn't done. I know where it's going; I know what the end-point for all of the characters I've introduced is, although some of those endings are based on characters that I haven't introduced yet. And one or two have changed since 1994, because of characters that have been introduced subsequently (this isn't really a spoiler – but or people who've read these books, an example: I knew where Kallandras was going to end up at the conclusion of the End of Days sequence, and now … it's not as clear.)
The Sagara Luna novels are my first attempt to do something different. I wanted to write novels that would a) stand alone and b) work in concert – much the way a Buffy season does. I also wanted to write something that had a much more accessible tone, something contemporary in feel, even with all the strangeness of the world around it. They're fun books to write. But they're actually harder, in some ways, for me. The language, the metaphors, the tone of the West novels – those are my writing voice. That's the voice I write in when I'm not really parsing words qua words; when I'm deep into story, and it's the story that's driving everything, hell bent on arrival. The Sagara tone is completely different, and I often find I'm stripping out metaphor or a turn of phrase that doesn't work with a contemporary feel when I do my first pass line-edits.
I thought of the first Sagara book as my attempt to write a Tanya Huff novel, with the clear understanding that I'm not Tanya Huff. I would like to be one tenth as witty or clever. I'm digressing.
People have read the Luna novels, and this makes me happy. People have even liked them, and have written to tell me so, and this makes me unreasonably happy. It's good to know that something you've tried actually works.
But … I'm not at all certain that the readers who liked the Luna books will actually like the West novels – and that's where reasonable reader expectation comes in. They are very different. But they are both written by me. I would have bet against it, but some people clearly do like both – and I'm completely uncertain about what to say when someone in the store asks me whether or not they should read the West novels if they like the Luna ones – or vice versa.
It doesn't do me any good – it doesn't do my career any good – to give people a novel that they don't actually want (it in fact helps no one's career to do this, in my experience). I've so far only had one person say "If you can write something good, why are you writing something boring?" in reference to the difference between the two. (Obviously I consider neither boring, because anything that bored me would never get finished; it's hard enough to finish something that's almost an obsession).
So the bookstore girl behind the writer wants to know how to navigate that minefield without denigrating either identity.