Have you read Amazon's best-selling book of 2015?

Story highlights

  • "The Girl on the Train" is the No. 1 best-seller of the year on Amazon
  • Two nonfiction works -- and two coloring books -- made the top 20
  • Many familiar authors are also on the list

(CNN)Harper Lee's "Go Set a Watchman" may have been Goodreads' best fiction book of 2015.

Ta-Nehisi Coates' "Between the World and Me" may have dominated honors given to the year's literary output.
But when it comes down to what sold the most copies on Amazon.com -- the country's biggest online bookseller -- the winner is Paula Hawkins' "The Girl on the Train."
    Amazon put out its list of 2015's best-sellers today, and the selection was an intriguing mix of history, potboilers and mystery, with Hawkins' debut novel -- about an alcoholic woman struggling to remember a possible crime -- at No. 1.
    Second on Amazon's list is E.L. James' version of "Fifty Shades of Grey" as told from Christian Grey's point of view, "Grey."
    Lee's controversial "Watchman," an early draft of what became "To Kill a Mockingbird," was No. 3. However, it was the best-selling print book, while Hawkins' tome led Kindle downloads.
    Veteran best-selling authors also had their places in the top 20. David Baldacci, Lee Child, John Grisham and Nora Roberts all made Amazon's list, as did Erik Larson and David McCullough, writers of the top 20's only nonfiction works, "Dead Wake" and "The Wright Brothers," respectively.
    Notably, two coloring books made the top 20, a sign that the trend hasn't flagged.
    1. "The Girl on the Train" by Paula Hawkins
    2. "Grey: Fifty Shades of Grey as Told by Christian" by E.L. James
    3. "Go Set a Watchman" by Harper Lee
    4. "The Nightingale" by Kristin Hannah
    5. "Memory Man" by David Baldacci
    6. "Make Me: A Jack Reacher Novel" by Lee Child
    7. "Rogue Lawyer" by John Grisham
    8. "The Girl in the Spider's Web" by David Lagercrantz
    9. "Dead Wake: The Crossing of the Lusitania" by Erik Larson
    10. "Silent Scream" by Angela Marsons
    11. "14th Deadly Sin (Women's Murder Club)" by James Patterson with Maxine Paetro
    12. "Old School: Diary of a Wimpy Kid Book 10" by Jeff Kinney
    13. "Enchanted Forest: An Inky Quest and Coloring Book" by Johanna Basford
    14. "The Wright Brothers" by David McCullough
    15. "Adult Coloring Book: Stress Relieving Patterns" by Blue Star Coloring
    16. "The Liar" by Nora Roberts
    17. "Luckiest Girl Alive" by Jessica Knoll
    18. "The Crossing" by Michael Connelly
    19. "The Stranger" by Harlan Coben
    20. "A Spool of Blue Thread" by Anne Tyler