"I consider an essay to be the biography of an idea," says Richard Rodriguez. Yes, ideas not as airy abstractions but as lived, embodied and temporal things. Richard's writing has always balanced intellectual sweep with lyrical particularity, threading its way between big-picture cultural criticism and intimate memoir. In his latest collection he is as broad and deep as ever, musing on faith in the dark days after 9/11; Judaism, Christianity and Islam as "desert religions"; his own relationship to Catholicism and his argument with the "new atheists"; the role of women in his emancipation as a gay man; and finding a way to live in love and live with death. Richard brings the same intensity and acuity to conversation as he does to the page, which made this interview a special one.

Two hundred years ago James Tilly Matthews described a sinister political plot using the latest technologies to influence official opinion and plunge England into war. He was branded a lunatic and sent to the notorious Bedlam insane asylum. But was Matthews really bonkers, or was he just ahead of his time? Historian Mike Jay says Matthews' dark vision of technology-assisted conspiracy has become a defining idea of our own age. How reality caught up with paranoid delusions.

James Dawes has written extensively on atrocity and trauma, but he'd never encountered flesh-and-blood perpetrators until he visited Japan in 2008. He went to interview reformed war criminals from the genocidal Sino-Japanese War of the 1930s and 40s, when Japanese forces raped, tortured and killed millions of Chinese. His meetings with the now-elderly men, and the memories they shared with him, left him unnerved and beset by questions. After some years of processing the experience, he's written a wide-ranging meditation on the causes and nature of inhumanity, the stories we tell about it and the very complicated business of bearing witness.

In this interview, filmmaker Henry Jaglom describes the Orson Welles he knew and loved. Their friendship began in 1970, when the upstart Jaglom impertinently asked Welles to be in his first movie ("A Safe Place") and the master improbably assented, and it continued until Welles's death in 1985. They were frequent dining companions at LA's then-trendy Ma Maison, and Henry recorded many of their conversations. Now film historian Peter Biskind has transcribed and edited some of the Welles-Jaglom tapes into a book, "My Lunches with Orson." Though the dishy parts have drawn most of the media attention, I was more interested in the sheer breadth and insight (both Orson's and Henry's) on display.

I've had music writer Don Cohen on the show previously, discussing two of his favorite musical genres: Portuguese Fado and Argentine Tango. He joins me again with his latest book, "Gypsy Voices: Songs from the Romani Soul," which collects Roma songs from the Balkans, Romania, Hungary and other parts of eastern/central Europe. We talked Roma history and music while playing tracks (some classics, some lesser-known) from the book's companion CD and doing our best not to overuse the term "Gypsy."

Joshua Oppenheimer isn't the only documentary filmmaker to aim his lens at the perpetrators of atrocities. But he may be the first to find such willing subjects. In his new film The Act of Killing, former Indonesian death squad members are only too pleased to describe their participation in the anti-communist purges of 1965-1966, when they helped butcher anywhere from 500,000 to more than a million people. So enthused were the aged genocidaires that they took an active role in Oppenheimer's project, re-enacting their youthful exploits for the camera. Werner Herzog, who served as executive producer with Errol Morris, says, “I have not seen a film as powerful, surreal, and frightening in at least a decade… it is unprecedented in the history of cinema.” Joshua Oppenheimer has been interviewed relentlessly as The Act of Killing debuts across the country, so when I got my chance, I tried to skip some of the compulsories and dig a little deeper into the details of the film and the queasy questions it raises.

Composer Kevin Puts returns to this year's Cabrillo Festival of Contemporary Music with his new Flute Concerto and a Pulitzer Prize on his credit. Kevin and I talked about the new work and its charming backstory; about his love of heartfelt music, whatever proponents of modernist abstraction may say; and about his choice of a contemplative composing career over the athletic rigors of concert piano. In the second part of the show, globe-trotting composer/clarinetist Derek Bermel describes Dust Dances, an orchestral piece based on his studies of the West African xylophone known as the gyil. Both Dust Dances and the Flute Concerto will be performed on opening night of the Cabrillo Festival.

David Hoffman picked up his first spring-wound Bolex 16mm movie camera in 1963. Over the next five decades he proceeded to make scores of films on a huge range of subjects: profiles of famous and not-so-famous people; music docs (including BB King at Sing-Sing, Earl Scruggs, Bob Dylan, Joan Baez); political, historical and military docs for public television; documentary-style commercials for Mobil Oil and other companies; and one notorious film that challenged the whole documentary form. He's still at it. David and I discussed his prolific career, his adventures behind the camera and his thoughts on truth and fabrication in documentaries.

If you fretted that you were merely a billiard ball on the pool table of life, Dan Dennett says take heart: you're actually a team of tiny robots. Dennett is often cast as the arch-reductionist, but he's actually more of an emergentist, as you'll hear in this interview. I've been wanting to talk to him again ever since we discussed his religion-as-biology book "Breaking the Spell" in 2006. We didn't have time then to get around to what he considers his life's work on mind, consciousness and free will. So when an opportunity finally came up last week, I did my best to cover all that ground in the hour Dan granted me.

Our previous interview with jazz/soul singer/songwriter Gregory was surely one of our best shows of 2012, and this second one picks up where the first left off. We talked about his precocious taste for jazz, performing gospel in church, the influence of his minister mother and her message of love even in the face of hate, turning life into song, and his seemingly meteoric – but actually long-in-the-making – rise on the jazz scene. We listened to some of Gregory's recorded music and some that hasn't been recorded (at least not until now), including his first original song, composed at the age of six.