Cutting for Stone by Abraham Verghese

Marion and Shiva Stone are twin brothers born of a secret union between a beautiful Indian nun and a brash British surgeon. Orphaned by their mother's death and their father's disappearance, bound together by a preternatural connection and a shared fascination with medicine, the twins come of age as Ethiopia hovers on the brink of revolution. Moving from Addis Ababa to New York City and back again, Cutting for Stone is an unforgettable story of love and betrayal, medicine and ordinary miracles--and two brothers whose fates are forever intertwined. This sweeping, emotionally riveting novel that "shows how history and landscape and accidents of birth conspire to create the story of a single life" (Los Angeles Times).