Question: is the movie a simple favor based off a book

Answer: Yes, A Simple Favor is an upcoming American mystery thriller film directed by Paul Feig and written by Jessica Sharzer. Based on the novel of the same name by Darcey Bell, the film stars Anna Kendrick and Blake Lively and follows a small-town blogger who tries to solve the disappearance of her mysterious and rich best friend. It will be released in the United States on September 14, 2018.