Paul Allen talks to Richard Weston, author of The House in the 20th Century, about the variety of architectural solutions to the problem of how to put a roof over one's head and considers the house as a work of art in itself. Also, Roots remembered: to mark the 25th anniversary of the television series Paul Allen discusses Alex Haley's Pulitzer Prize-winning novel, Roots, which told the story of the slave Kunta Kinte and his descendants.