The Netflix true-crime series “Making a Murderer” has performed a public service by highlighting conflicts in the criminal-justice system, the writer Bill James says. PHOTOGRAPH BY NETFLIX / EVERETT

Five years ago this month, Bill James revealed a new twist in his unlikely career. James first achieved notice, beginning in the nineteen-seventies, by self-publishing math-heavy tracts about baseball while working security at a pork-and-beans factory in Lawrence, Kansas. He became the godfather of the advanced statistical analysis of sports, and his techniques soon spread into other areas of knowledge. (He was profiled for The New Yorker by Ben McGrath, in 2003, after he took a job with the Boston Red Sox.) His writing was a critical influence for Nate Silver, among many others—it’s possible that data-journalism outlets such as Silver’s FiveThirtyEight and the Times’ The Upshot would not exist without the groundwork laid by an amateur on the prairie with an addiction to watching the Red Sox on TV (which James pronounces “TEE-vee”).

But with “Popular Crime,” published in 2011, James announced himself as an authority in a second, totally unrelated field. It is the kind of book that only an already famous person gets to publish, and one could reasonably expect it to be awful. Instead, the book has become something of a cult favorite among the crime-obsessed. James leads a winding tour through nearly every famous American criminal case, cramming in a truckload of barroom speculation, oddball original thinking, and merciless logic. He shows a winning aversion to pretense, formality, and bullshit. James writes more casually than anyone who writes better, and he writes better than anyone who writes more casually.

“Popular Crime” is both a survey of true crimes and a survey of true crime as a genre; James did not conduct original reporting about, say, the Rosenberg case or Natalee Holloway’s disappearance, but he immersed himself deeply in the available material. He writes with brisk self-assurance about each crime, opining on the best and worst of the coverage, offering theories about the case, and teasing out the lasting significance.

Since the book was published, true crime has come to occupy a more central role in American popular culture, with the runaway success of several works in relatively quick succession: the podcast “Serial,” the HBO series “The Jinx,” the Netflix series “Making a Murderer,” and, most recently, two separate miniseries about the O.J. Simpson case.

I spoke to James about the current infatuation with “true crime,” the enduring importance of the genre, and his next book, about a series of murders committed more than a century ago. We spoke on his wife’s cell phone, because he couldn’t get his working, and continued exchanging e-mails while he travelled to Boston to watch the Red Sox, as he often does in his role as a senior advisor to the team. Our conversation has been edited and condensed.

Are you surprised by the reception of these recent crime works? In your book, you write, “If you go to a party populated by the NPR crowd and you start talking about JonBenet Ramsey, people will look at you as if you had forgotten your pants.” But these recent shows have been taken seriously.

I wouldn’t say surprised. I’m glad to see it. I’ve always thought that these events are significant and serious events and people should pay attention to them. I’ve always thought interest in what I call popular-crime cases is a harbinger or a forerunner of some sort of effort to fix the justice system. Let’s hope that that is true. I was really pleased to see the popularity of “Making a Murderer.” Because it’s my experience that people are reluctant to believe in the concept of false confessions. And here’s a case where it’s really obvious where confessions are dragged from a person under great duress and he’s not actually guilty. It’s useful to see those things and say, “Oh, I see how that happened.”

You’re referring to the younger defendant, Brendan Dassey?

Yes.

Even with material in a more highbrow register, though, such as “Serial” and “Making a Murderer,” people argue that the genre is exploitative, that the victims get short shrift, that there is something distasteful about turning real tragedies into entertainments.

Well, certainly there is something distasteful about it. But of course we ask what happened to cause this tragedy; I don’t see how anyone can argue the point. When there is a car wreck, we ask what happened to cause the car wreck. We should not look away when someone dies in any preventable fashion.

But aren’t there true-crime books that you found morally repellent?

I think I have run across one or two. But then, NPR sometimes seems to me to do stories which are morally repugnant. What I find most offensive, honestly, is self-righteousness, the assumption of moral superiority. If people refuse to look at what really happens because “well, you know, we are not the kind of people who take an interest in that kind of thing”… I find that more offensive than anything I have ever run across in a crime book.

Your tastes run the gamut in this genre. You said you were planning to watch a program about the Chillicothe murders on the cable network IDTV. I have not watched that channel but I am guessing it is not pitched to what you call the NPR crowd.

It isn’t. I check what’s on IDTV whenever I sit down with the Red Sox on. Most of it is terrible, and a lot of it is unmentionably terrible. However, that’s generally true. I mean, most analytical writing about baseball is unreadable. Most artwork that’s done in any genre is dreadful.

The thing is, you still have to go to sort of disreputable media to follow certain kinds of stories. In the case of, say, artwork or music or films, there is a mechanism to elevate that work which is worthwhile. I feel like the prim and proper news supervisors do not do that in this field. The work that is good gets no more attention than the work that is terrible.

I would think it takes an intense fascination to get through all the dreck that you have consumed. Why are you so invested?

Well it’s a clichéd answer, but it’s the honest answer anyway: the interest is that crime stories are about those parts of ourselves that we hide, those parts of ourselves that we deny and don’t want to admit are there: lust, greed, anger. As to being singularly fascinated, well, turn on your TV. There are, at this moment, forty channels on your TV doing crime stories, whether true or fictional. If you look at the Bible, there’s a crime story on every page. Almost literally. I don’t think it’s an unusual fascination.

Your book demonstrates quite a lot of confidence about a number of cases. You utterly convinced me, as someone who had only casually followed the case, that JonBenet Ramsey’s parents are innocent in her death. But people have been debating this case for twenty years. How can you be so sure?

In that case I was certain in my own mind and adopted the position that the truth was clear and I was going to argue for it. I don’t think there are many cases like that in the book.