British comic Shazia Mirza has been taking her act to places where stand-up comedy is virtually unknown, and the spectacle of a woman cracking jokes on stage is almost revolutionary. Some audiences are ready for it, and some aren't. We talked about the sometimes surprising reactions she's gotten in Pakistan, India and back home in England.

Do I have to write a description of this interview? Can I simply say, “just listen”? Since his debut album came out in 2010, jazz/soul singer Gregory Porter has quickly won a passionate following around the world. It's easy to see why: there's so much depth and warmth and poetry in his vocals and compositions. And as our conversation made clear, those qualities come straight from the man himself. So just listen, and don't miss the end.

We've talked to Errol Morris about his investigative ardor in our previous conversations, and we've mentioned his decades-long delvings into the case of Jeffrey MacDonald, the Green Beret doctor serving life in prison for murdering his wife and children. This time we get into the details, working our way through the evidence and Morris's contention that MacDonald was railroaded. Morris says the investigation was bungled from the beginning (one forensic expert called it a "colossal clusterfuck"), and that MacDonald was the victim of a peremptory narrative that blinded the police, the courts and the public to many of the facts. Errol's new book "A Wilderness of Error: The Trials of Jeffrey MacDonald" isn't just a meticulous anatomy of a murder case, but a sobering reflection on our sometimes wayward truth-finding process and justice system.

Down the mean streets of old Hanoi goes Mike Vann, a historian specializing in Vietnam during its nearly 70 years under French rule. Mike has uncovered some wonderfully tawdry tales that reveal a lot about the whole strange business of colonialism, when much of the globe was claimed by a handful of European countries. We discuss sex in the colonial city, the great rat massacre, murder on the Rue Hue, Hanoi in the time of cholera, and some charming French postcards.

Jim Holt is a rarity: a writer who throws light on some of the most daunting problems in physics, philosophy and math in ways that are impressively knowledgeable, artful and entertaining. He's outdone himself in his latest book, "Why Does the World Exist: An Existential Detective Story," which confronts the enigma of existence itself, considered from the perspectives of physics, metaphysics and theology. As Kathryn Schulz wrote in the New York Times, "the book is deep, absorbing, associative, challenging, and makes you laugh, unexpectedly and a lot" – much like my experience talking to Jim in this interview.

Originally broadcast in Feb 2011, my conversation with theoretical physicist Anthony Aguirre on the new, more complex picture of the universe that cosmologists have been sketching out in recent years. Anthony gave some of the clearest explanations I've heard of eternal inflation, the multiverse and why the Big Bang might not have been the beginning of everything.

I continue interrogating the interrogator in this second of two wide-ranging conversations with filmmaker/detective/truth-seeker Errol Morris. Among the many subjects discoursed on: Whether and how much the past can be recaptured through the art of investigation; Errol's latest book "A Wilderness of Error," about the Jeffrey MacDonald murder case; how he gets people to spill the beans on camera; Errol's beef with his former PhD adviser, historian of science Thomas Kuhn; and his next movie (The Fog of War with more fog?).

Errol Morris's relentless search for answers – philosophical, psychological, forensic – has led to a vast and ever-growing body of work that includes his celebrated documentaries, dozens of short films, weighty essays (and cognitive experiments) in the NY Times, books, actual criminal investigations and some pretty fetching commercials.The backstories are as interesting in some ways as the finished products, and Errol shared some of them with me in a very illuminating look at his career, his preoccupations and motivations.

An hour-long interview wasn't enough to cover but a fraction of Lou Harrison's many accomplishments, but Eva Soltes and I did our best to hit some of the high points. Her new documentary, "Lou Harrison: A World of Music," uses footage she shot during her decades-long friendship with the eminent American composer, musical innovator and political activist, who died in 1982. The film was recently screened as part of the Cabrillo Festival of Contemporary Music, which Harrison helped found and which is honoring him this year with a performance of his Third Symphony.

As an Emmy-winning soundtrack composer for TV and film and as a session/backing musician (piano, violin, viola), John Wineglass can write or play just about anything. Gospel, classical, R&B, country, folk, Latin – he can swing it. But it's his serious concert works he's most proud of, like his new orchestral piece Someone Else's Child, premiering at the Cabrillo Festival of Contemporary Music on August 4. We discussed the new composition, John's dual-track musical education – playing classical in a well-known youth orchestra and gospel in church – and his jack-of-all-genres commercial work.