This week's broadcast, featuring guest host Lee Cowan, included Susan Spencer's cover report on conspiracy theories, and why some many people are attracted to them to explain seemingly inexplicable events. Plus: Rita Braver interviews former Gary Hart, whose presidential campaign in the 1980s, upended by allegations of an affair, is dramatized in the new film "The Front Runner"; Anthony Mason profiles singer-songwriter John Prine, whose latest album, "The Tree of Forgiveness," is the biggest hit of his long career; Martha Teichner interview potter and bestselling author Edmund de Waal; Cowan meets rising star and Grammy-winner Alessia Cara; and Luke Burbank meets the inventor of the waterbed, who has introduced a "new and improved" version.