"The Midnight Library" is a novel by Matt Haig that explores the concept of choices and regrets. The story follows Nora Seed, a woman who finds herself in a magical library between life and death. Each book in the library represents a different life she could have lived based on the choices she made. As Nora opens these books, she experiences various alternate realities, discovering the impact of her decisions. The narrative delves into themes of hope, fulfillment, and the importance of embracing life, ultimately guiding Nora toward understanding her true desires and the value of her existence.