For those who have published books, the answer would of course be, “Hopefully as large as possible,” but did you expect a particular number, like, “I think my book will, at most, be read by 300 people?” Does the size of your expected audience affect how you write your book?
I feel like, the smaller the expected audience, the more latitude and freedom an author may actually have, since he will be catering to a smaller and more specific demographic.
I did absolutely nothing to publicise my book, so my expectations were pretty low! Total sales are in the area of 40-50 I’d say.
I have no idea hoe big my numbers are. If I kept track of royalties over the years I could calculate it, I suppose. But based on estimates alone, most of my books have disappointingly low readership. The one exception is my first book, Medusa, which continues to sell even after being in print for a quarter of a century. Its royalties paid off my advance, and I get a small sum every year, so it must be doing pretty well. I suspect that Classics professors keep assigning the book for classes. That’s a winning formula – write a textbook that gets adopted.
My second best book is probably Lost Wonderland, and for two reasons that are unrelated to the quality of the book – It’s distributed by Ingram, which is the best distributor to have. It’s not who publishes you; it’s who distributes you. Booksellers LOVE Ingram. So they’ll stock this book, but not my others. In addition, UMass Press has kept the price pretty low, unlike my other publishers. That ensures that my book can get into bookstores and can sell. If you don’t have professors requiring your books for courses, this is probably your best strategy.
I ought to add that my purpose in writing these books was to try to get my ideas i n front of as many people as possible. That the best way to do this is to do what leads to most sales (and biggest royalties) isn’t a coincidence. It’s just that “biggest” is a relative term. Medusa was an unqualified success at spreading the word. But I’m not going to retire on my royalties.
My readership is in the low 1000s. No, I don’t think it changed how I was writing compared to before I was published, and expected only a few people to read my work.
I think you have to write to your genre / niche. But that can be just as constraining whether it’s big or small.
And, of course, you have to get used to writing as though your parents won’t read it!
According to Worldcat.org, which is a site where you can look up which libraries have your book, we’re in 132 libraries at least. Actually a lot more, since many public libraries don’t subscribe. I have no idea of how many times the book is checked out in them.
Bloomsbury Academic sells mostly to libraries, and is not all that interested in wider sales, and the price point is too high for museums, alas,