Last month, David Koch came to the Chicago StoryCorps booth with his youngest son, Matt. They talked about Matt’s mom, Lisa, who was diagnosed with breast cancer while pregnant with him, and Matt used the occasion to ask his dad a big question.

StoryCorps’ mission is to provide Americans of all backgrounds and beliefs with the opportunity to share, record and preserve their stories. These excerpts, edited by WBEZ, present some of our favorites from the current visit, as well as from previous trips.