Well, the popularity of this week's best - selling fiction novels can be attributed to multiple factors. Firstly, the writing style plays a huge role. If the author has a way with words that is both accessible and beautiful, like in 'The Alchemist', it can attract a wide range of readers. Secondly, current cultural trends can also impact sales. If a novel touches on a topic that is currently in the public eye, such as mental health in 'It Ends with Us', it's more likely to be popular. And of course, positive reviews and word - of - mouth recommendations are key. If a book gets a lot of buzz on social media or from book clubs, it'll climb the best - selling lists.