Jonathan Eig’s book “King: A Life” is the first comprehensive biography in decades of Martin Luther King Jr., drawing on reams of interviews and newly uncovered archival materials to paint a fuller picture of the civil rights leader than we have received before. On this week’s podcast, Eig describes the process of researching and writing the book, and tells the host Gilbert Cruz how he tracked down resources that were unavailable to earlier biographers.“I was a newspaper reporter for a long, long time — and you know, working on daily stories, if you got five days to work on a story, it was a luxury. Now I’ve got five, six years to work on a story, and I take full advantage of that," Eig says. "It took me two years to find, even though I knew it was out there, this unpublished autobiography that Martin Luther King’s father wrote. Nobody had ever quoted from it. ... Stuff like that just gets me really, really pumped up.”We would love to hear your thoughts about this episode, and about the Book Review’s podcast in general. You can send them to books@nytimes.com.