Bittersweet: How Sorrow and Longing Make Us Whole is a 2022 book written by American author Susan Cain. Bittersweet is based on the premise that "light and dark, birth and death—bitter and sweet—are forever paired". Cain encourages the reader to accept feelings of sorrow and longing as inspiration to experience sublime emotions—such as beauty and wonder and transcendence—to counterbalance the "normative sunshine" of society's pressure to constantly be positive. The book advises that sensitivity to the bittersweet—both the bitter and the sweet in life—elevates our way of creating, leading, raising children, loving, and achieving a deeper and more enriching life.