All relationships have a backstory, even friendships. Best friends Aminatou Sow and Ann Friedman, hosts of the podcast Call Your Girlfriend, are out with a new book called Big Friendship: How We Keep Each Other Close. In it, they write about their friendship story and they share lessons for all of us about how to keep our own friendships strong. Sam chats with them about going to friend therapy and what it's like to have a deep friendship with someone of a different race.Follow us: https://twitter.com/NPRItsBeenAMin Email us: samsanders@npr.org