So who is Pappy Pariah and why is Sean Penn saying all those nice things about him? Little or no light was shined on the not particularly difficult mystery Friday when the actor appeared on HBO’s Real Time With Bill Maher. The guest spot was the two-time Oscar-winner’s second Pappy plug this week – he appeared Tuesday on The Late Show With Stephen Colbert – to promote the oddly-named author’s “mem-noir” Bob Honey Who Just Do Stuff.

Penn narrates a free audiobook of the Pariah roman a clef, available October 18, which Maher described as a “beautifully written” fever dream about a former intelligence agent-slash-sociopathic killer. “First of all,” praised Maher, “it’s short, which I love.”

Maher seemed, surprisingly, rather more accepting of Penn’s non-authorship than was Colbert. Penn repeated the story that he’d met the book’s author once in passing in 1979, and hadn’t reconnected until May of this year, when he received Pariah’s unsolicited manuscript from the Cayman Islands.

“What I was reading was, in essence, the book I would have written if I was writing a book,” Penn told Maher, seeming to offer bait that went unchomped. (Colbert wasn’t so accepting – despite Penn’s denial that he wrote the book, the Late Show host noted, at one point, “That sounds made-up”).

HBO hadn’t posted an online video clip of Penn’s Real Time appearance as of Saturday morning. Deadline will link to a clip if and when it becomes available.

“He has a clear moral code,” said Penn about the book’s title character who has spent some time with drug lords, “that has to do with something that we’ve always had trouble with in terms of morality, which is the principle of triage – what you treat first. For example, he talks about words being as lethal as a gun but nobody needs a background check for the words.”

Continued Penn, “There’s a kind of exploration of the chaotic part of what’s happening in culture, for example the Trump voters – and quite clearly one of the characters is Donald Trump. Those voters are in one of two categories: they are either the highly uninformed – and we could use a less polite word for some of them – and you’re also looking at a country of people who are truly unwittingly willing to dismiss their love for their children to engage in a kind of political temper tantrum.”

Donald Trump himself came out relatively – relatively – unbruised from Penn’s appearance, aside from getting labeled “a 12-year-old sociopath.”

Despite Penn’s spotlighted top-of-the-show slot, he never really got around to answering Maher’s opening question – “Why are you plugging someone else’s book?” Maybe the actor will explain further when he does a Bob Honey reading Thursday October 6 at the Los Angeles County Museum of Art. No word yet on whether Pappy Pariah will show.