Biblioteka O Północy by Matt Haig

A lonely, depressed woman on the brink of death finds herself in a mysterious library between life and death where a compassionate librarian offers her the chance to open books that let her live out alternate versions of her life based on different choices; as she explores careers, relationships and regrets—from fame to quieter, more ordinary paths—she confronts the weight of “what if,” learns how small decisions and connections shape meaning, and gradually discovers reasons to accept and re-engage with her own life.