On May 15th’s episode, Gilbert and Frank talk with producer, archivist and fellow Marx Brothers fanatic Robert S. Bader about his lifelong obsession with the boys as well as his fascinating (and meticulously researched) new book, “Four of the Three Musketeers: The Marx Brothers On Stage.” Also: Gummo goes to war, Harpo “courts” Amelia Earhart, Grouchocashes in on “Skidoo” and Gilbert hangs with Chico’s daughter. PLUS: Swain’s Rats & Cats! The real-life Sunshine Boys! BugsySiegel buys the farm! Dennis Hopper plays Napoleon! And the mystery of the disappearing Marx Brother!