My wife wrote a book in a previous tax year, which is published by a trade association in her field and received a 1099-MISC for a bit under $600 in royalties. Her primary source of income is a job in the same field as the topic of the book, but writing is not her primary profession. This isn't the case, but say she was a tax accountant who wrote a book for other accountants about filing client taxes and it was published by an accounting trade association. How should we claim that income -- Schedule C or Schedule E?
If it matters, she is currently writing another book for the same publisher, but will not be paid anything for this book until sales are made. If this does matter, do things change if she doesn't continue to write in a future year, but does continue to receive royalties?