Fiction: The Midnight Library by Matt Haig

Somewhere out beyond the edge of the universe there is a library that contains an infinite number of books, each one the story of another reality. One tells the story of your life as it is, along with another book for the other life you could have lived if you had made a different choice at any point in your life.
When Nora Seed finds herself in the Midnight Library, she has a chance to make things right. Up until now, her life has been full of misery and regret. She feels she has let everyone down, including herself. She must search within herself as she travels through the Midnight Library to decide what is truly fulfilling in life, and what makes it worth living in the first place.
But things are about to change.