"The Impossible Lives of Greta Wells" is a novel by Andrew Sean Greer that follows the life of Greta Wells, a woman in 1985 who is struggling with the loss of her twin brother. In her quest for healing, she undergoes a series of experimental treatments that unexpectedly transport her to different time periods, including the 1918 flu pandemic and the 1940s. As Greta navigates these alternate lives, she encounters various versions of herself and her loved ones, exploring themes of love, loss, and identity. The story blends elements of historical fiction and magical realism, offering a unique perspective on the choices that shape our lives.