However, here are some authors who were very popular in 2017, based on various metrics:
* J.K. Rowling: While not technically a new release, the release of "Harry Potter and the Cursed Child" in 2016 continued to generate massive interest in 2017, and her "Fantastic Beasts and Where to Find Them" film also added to her popularity.
* Stephen King: His constant output and popularity were undeniable. He released "It" and "Sleeping Beauties" in 2017, both of which were major successes.
* John Green: He continued to be a bestselling YA author with "Turtles All the Way Down," released in 2017.
* E.L. James: The final installment of her "Fifty Shades" trilogy, "Fifty Shades Freed," came out in 2017, guaranteeing her continued popularity.
* James Patterson: As a prolific author, Patterson consistently releases new books, often collaborating with other authors. His popularity was evident in 2017 with his numerous titles on bestseller lists.
Ultimately, determining the "most popular" author depends on the specific metric you are using.