(Note: This interview originally aired back in April.) Our guest is Marc Perrusquia, a journalist with the Memphis Commercial Appeal newspaper, where he's worked for the past three decades. Perrusquia has a new book out, a very compelling work of history called "A Spy in Canaan: How the FBI Used a Famous Photographer to Infiltrate the Civil Rights Movement." As was noted of this book by Kirkus Reviews: "The story of an African-American photographer who spent 18 years feeding information to the FBI.... Over a 60-year career, Ernest Withers (1922-2007) produced more than 1 million photographs chronicling black life in the South. A 'pivotal' contributor to the black press, he seemed an unlikely man to serve as an FBI informant. His powerful images of Martin Luther King Jr., of Emmett Till's uncle at the trial of his nephew's killers, and of civil rights and anti-war protests appeared to support the activities and individuals he documented. But as Perrusquia...argues persuasively, from 1958 to 1976, Withers led a 'double life.' A trusted member of the Memphis black community, he was trusted as well by FBI agent William Lawrence, who filled dossiers with photographs and intelligence Withers passed on.... Perrusquia is uncertain about Withers' motivation -- "money, patriotism...[or] his long ambition to be a cop" -- and he sees him, as do many others, as a hero who publicized the realities of activist movements. [This is a] fast-paced story of a man at the center of turbulence and paranoia."