In “Station Eleven,” she explored fallout from a pandemic. Now, in “Sea of Tranquility,” Mandel takes up existential questions of time and being.In “Station Eleven,” she explored fallout from a pandemic. Now, in “Sea of Tranquility,” Mandel takes up existential questions of time and being.Read MoreSea of Tranquility (Book), Mandel, Emily St John, Books and Literature