WNYC's Anna Sale talks about President Obama's speech last night at the Democratic National Convention in Charlotte.

Andy Borowitz, author of The Borowitz Report on the newyorker.com, talks about what we learned from the conventions.

Carol Blue, the widow of Christopher Hitchens, discusses his last book, Mortality, a collection of his series of award-winning columns for Vanity Fair, written over the last year of his life. In this account of his affliction, Hitchens describes his battle with esophageal cancer and explores how disease transforms experience and changes our relationship to the world around us.

Football legend Floyd Little talks about his journey from poverty to military school, college, the NFL and the Pro Football Hall of Fame. In Promises to Keep: My Inspired Run from Syracuse to Denver to the Hall, he shares his favorite tales from his first high school game, his time playing for Syracuse and for the Denver Broncos. He also recounts stories about fellow Hall of Famers of his era, his Broncos teammates, and shares his thoughts about today's NFL stars.

Monarch butterflies have started to make their long journey south to Mexico. On this week’s Please Explain, we’ll find out about the many different species of butterflies—from their coloring to their attraction to flowers to their cocoons. We’re joined by Bob Robbins, Curator of Lepidoptera, Smithsonian Institution National Museum of Natural History, and Dr. Cole Gilbert, Associate Professor of Entomology at Cornell University.