Even if you’ve never read one of Richard Price’s novels, there’s a good chance you’ve been acquainted with his work as a screenwriter on films like Pacino’s late ’80s comeback Sea Of Love, Scorsese’s The Color Of Money, the Mel Gibson vehicle Ransom and Spike Lee’s film of his book Clockers. Yet despite the day job, Price is a writer’s writer. His latest book Samaritan comes bearing garlands from Elmore Leonard and Stephen King on the dust jacket, and it’s no idle case of cronyism or literary logrolling.

Leaving aside the kind of taut plotting and exemplary characterisation one would expect from an A-list script doctor, Price’s eye for detail is uncanny, nailing the moments that happen between the lines, the gestures and tics and idiosyncrasies that tell you more about the protagonists and their motivations than any amount of blather. Hardly surprising then that his scripts come crammed with notes in the margins.

“See, the funny thing with the scripts is, all a director wants from a writer is the story,” Price points out, “who says what, and physically what happens next. I did the script for Clockers and it was so obsessively (written), every nuance was down, and then Spike Lee took over and he rewrote the whole script, and his looked like it was scratched on the back of an envelope it was so thin. I said to him, ‘Where is everything?’ and he said to me – and this is a good explanation, even though I didn’t particularly like the movie – he said, ‘Look, you’re a writer. When you’re finished writing, you’re gone, you’re outta this project, therefore you’re gonna put in everything, every little note, it’s like leaving notes for the cleaning lady. I’m a director, I’m gonna be around, all I need to do here is make notes to myself.”

So what’s it like for Price watching the finished product on the screen?

“You can ever ask the novelist, ‘Did you like the movie?’” he chuckles. “On one hand, you’re grateful the cheque didn’t bounce, and then you go nuts because it’s not your novel. It doesn’t even make a difference if the movie is much better than the screenplay that you left them with – it’s still not the movie that was playing inside your head when you were writing.”

The pitch for the movie playing inside Price’s head when he wrote Samaritan might go something like this: Ray Mitchell, a well-off television scriptwriter, lies semi-conscious in his hospital bed having been brutally beaten. A local boy made good in Hollywood, Mitchell returned to his old stomping grounds on the New Jersey projects to tutor high-school kids on the craft of storytelling. He is visited in the hospital by a childhood acquaintance, Nerese Ammons, a black female detective on the edge of retirement, investigating the case as a favour to the school principal. Mitchell knows who did it, but he’s not saying, although Ammons suspects one of the writer’s pupils.

Samaritan works not only as a high-class thriller, but also as a study of the hidden consequences of altruism. The story stemmed from Price’s own experiences of trying to give something back to the deprived kids on his home turf.

“If I could generalise it, it’s about the intersection between, I dunno, narcissism and altruism,” he says. “Is it truly helping people if you’ve got one eye in the mirror admiring yourself helping people? Let’s say somebody needs money for something and you give it to them – that’s a clean deal. But if what you’re doing is implying that you’ll always be there for them, that’s nothing to do with dollars and cents, it’s got to do with this implied promise of spiritual support.”

By way of illustration, Price cites an incidence of helping out a single mother by playing male role model to her son for a day.

“You go off with this totally silent 11 or 12-year-old kid who’s never been out of the projects,” he says. “I take him across the river to New York city and spend the whole day with him, playing Santa Claus, either materially or via conversations, asking him about himself, being curious about him in a way nobody’s ever been before. And then, come the end of the day, I’m taking that kid back to his mother in the projects. And the kid, who’s never said thank you and never even smiled all day, in his mind he’s never had a day like that with an adult male, and his head’s on fire. I’m leaving that place, I’m thinking, ‘I wonder what’s on TV tonight?’

“I’m using myself as the sacrificial lamb in this story,” he continues, “but the fatal flaw is I don’t realise what I did to that kid, and because I don’t realise, it doesn’t ever bother me not to ever call that kid again. It’s playing with people’s lives. I don’t know how much press this got over with you, but there was an English teacher named Jonathan Levin in a very, very rough high school in the Bronx whose father was Gerald Levin, the head of Time Warner. And he cultivated a certain charismatic presence, he tended to make the students feel like it was him and them against the establishment, and he made himself extremely available, he’d give out his phone number and intercede for the kids with family.

“And at some point two of his former students showed up at his house in Manhattan and tortured and killed him for his cash machine card. I don’t really know anything about him except for the surface events of his life, but there’s something there that (says) he was playing with fire. It’s sort of like a fatal obliviousness to the people that you’re playing with, because you can get wrapped up in your own charisma and your own drama.”