For book sales: The sum is greater than the parts

So, here’s the question for the hour: Do I really need to publish 10 books to be successful? Yes! No! Maybe! Confused? Most authors are, or shouldn’t be surprised. 

Of course, success depends in part on how you define your goals. If your goal is to put your story on paper so that friends and family can read it, then publishing one book is a success. And, for the record, achieving that goal is a significant success.
If your goal is to be commercially successful, then your going to have to do a lot more work. And multiple books help. In fact, I believe multiple books will be essential for most authors if this is a goal. You may not need ten, but you will need more than one. (I’ve discussed this before here.)

The reality is that more books beget more success. Many of the most commercially successful writers have written a lot of books. Usually, it’s not just one or two or three. They’ve written five, ten or more. The first couple of books may have been commercial successes, but that might mean the book covers it’s publication costs even though the earnings to the author might not cover even a modest vacation.  
But, if your goal is to earn enough money to support yourself as a full-time writer, ten or more books is not that far off. In fact, it may be a necessary condition. I think sci-fi writer Doug Dandridge is a useful case study here. Doug quite his regular job to devote himself to full time writing in 2013. But, Doug couldn’t do this with just a couple of books out. In fact, Doug now has 14 books out and available through amazon.com. 
But, Doug’s success isn’t based on a “shot gun” approach to writing and publishing. He’s focused on a particular genre and writes books that appeal to similar audiences. In fact, Doug’s income does not depend on one book. Or two books. His income is generated from a portfolio of books that creates synergy with his intended readers. While at any given time one book may be selling hundreds of copies (or even dozens), his financial success depends on having a wide range of products that appeal to an increasingly broad reader base in his genre. His satisfied customers can continue to buy other books, leveraging the sales of one book into two or three. Check out some of Doug’s insights into his sales numbers for various books here, here, and here.
I also believe an important part of Doug’s success is that these books are in press. His readers and fans don’t have to wait to buy another book. 
This also explains why publishers like series, and often try to sign talented authors to multi-book deals. The sum is greater than the parts in books sales and marketing. 
So, for authors interested in making money, more is indeed better. 
Author: SR Staley
SR Staley has one more than 11 literary awards for his fiction and nonfiction writing. He is on the full-time faculty of the College and Social Sciences and Public Policy at Florida State University as well as a film critic and research fellow at the Independent Institute in Oakland, California. His award-winning Pirate of Panther Bay series (syppublishing.com) has won awards in historical fiction, mainstream & literary fiction, young adult fiction, and reached the finals in women's fiction. His most recent book is "The Beatles and Economics: Entrepreneurship, Innovation, and the Making of a Cultural Revolution" due out in April 2020 (Routledge).