We all have our past. It’s what molds us into who we are. The past is something we must live with and learn from. It’s just that, history. When we can learn to stop holding onto it or anxiously dreading something in the future, we can learn to...

Journalist Abigail Pogrebin is many things—wife, mother, New Yorker—but the one that has defined her most profoundly is “identical twin.” As children, she and her sister, Robin, were inseparable. But when Robin began to pull away as an...