How did you become involved with the subject or theme of your book?
Why did you choose to write in your particular field or genre? If you write more than one, how do you balance them?
Where did your love of books/storytelling/reading/writing/etc. come from?
How long have you been writing?
What kind(s) of writing do you do?
What cultural value do you see in writing/reading/storytelling/etc.?
How does your book relate to your spiritual practice or other life path?
What were your goals and intentions in this book, and how well do you feel you achieved them?
Can you share some stories about people you met while researching this book?
What are some of the references that you used while researching this book?
What do you think most characterizes your writing?
What was the hardest part of writing this book?
What did you enjoy most about writing this book?
Are there vocabulary words or concepts in your book that may be new to readers? Define some of those.
Are there underrepresented groups or ideas featured if your book? If so, discuss them.
Are there misconceptions that people have about your book? If so, explain.
What is the biggest thing that people THINK they know about your subject/genre, that isn't so?
What is the most important thing that people DON'T know about your subject/genre, that they need to know?
What inspires you?
How did you get to be where you are in your life today?
Who are some of your favorite authors that you feel were influential in your work? What impact have they had on your writing?
What did you find most useful in learning to write? What was least useful or most destructive?
Are you a full-time or part-time writer? How does that affect your writing?
What are some day jobs that you have held? If any of them impacted your writing, share an example.
For those interested in exploring the subject or theme of your book, where should they start?
How do you feel about ebooks vs. print books and alternative vs. conventional publishing?
What do you think is the future of reading/writing?
What process did you go through to get your book published?
What makes your book stand out from the crowd?
How do you find or make time to write?
Do you write more by logic or intuition, or some combination of the two? Summarize your writing process.
What are some ways in which you promote your work? Do you find that these add to or detract from your writing time?
What is your role in the writing community?
What do you like to read in your free time?
What projects are you working on at the present?
What do your plans for future projects include?
And my favorite for dealing with popular authors who've already done a lot of interviews:
What question do you wish that someone would ask about your book, but nobody has? Write it out here, then answer it.