I wrote my rave review of HBO's "The Leftovers" — which began with me wondering why on earth "Lost" co-creator Damon Lindelof would get involved in a show designed to not offer answers to a cosmic mystery — before I had a chance to sit down with Lindelof (pictured above with director Peter Berg and Justin Theroux) and Tom Perrotta (who wrote "The Leftovers" novel and co-created the series with Lindelof) and ask him that very question directly. His answer fit in with my assumption that he found the show's premise — 2 percent of the world's population disappears in a Rapture-like event called the Departure that equally baffles science and religion — freeing rather than constraining.

Over the course of an expansive discussion, Lindelof and Perrotta discussed the genesis of the Departure idea, their approach to adapting it for television, Lindelof's own experience as a bewitched and frustrated TV fan and whether his absence from Twitter — he last tweeted on October 14th, the date of the fictional Departure — was frustrating when his love of singers in oversized hats became a public phenomenon again. It's one of those conversations — and one of those shows — where we could have talked for three or four times the length of this chat and still not covered everything, but at a minimum I am trying to imagine a world where Lindelof is Nic Pizzolatto's gofer on "True Detective" season 2.

Given your obsession with Justin Bieber's hat, how much was it killing you to no longer be on Twitter when Pharrell's hat appeared?

Damon Lindelof:
There have been many pop culture instances over time where — like how when someone loses a limb, they have an itch on their stump — my tweeting thumbs would itch. But I don't know. I sort of embraced Pharrell's hat. It didn't catalyze me in the same way that Bieber's hat did. I felt like there was an awareness on Pharrell's part on what the hat was that Bieber completely lacked, which made it much more engaging to become obsessed with Bieber's hat.

Tom, where did the idea for this originally come from? You did a couple of religious books in a row.

Tom Perrotta: That's right. I was writing about the culture war in "The Abstinence Teacher" and reading and thinking about evangelical culture. And the fact is, tens of thousands of Americans believe that the Rapture is going to happen in their lifetime. Because I'm not especially religious, my first impulse is to think that's really odd, or even quaint. But then over time, I started to think, 'Well, what if it did happen?' That to me is the better writerly question: not to satirize the Rapture or people who believe in it, but just to imagine how would I respond to that? I wasn't interested in satirizing Christianity, but the idea got lodged in my head. And then I tweaked it by making it random, rather than the Christian Rapture, so that it was as much of a challenge to Christians as it was to non-believers. And once I did that in my own mind, it started to seem like a really interesting existential allegory.

One of the things I found interesting about the book and now the show is that most of the central characters are not people who lost someone in the Departure.

Tom Perrotta: To me, what's interesting is that there is not a single reaction to an event like this. The story is really about a range of reactions. Put most broadly, some people want to move on, and some people want to stop and ponder what happened, and to say that a new world started that day, and here's what that new world is. And other people want to say, 'Our lives are this ongoing flow of events, and that was just one event in it, but that story I was in before it is still the story of my life.' It's about the variety of the responses, individually and collectively.

Damon, what did you make of the book when you first read it?

Damon Lindelof:
I thought it was fascinating, on both a non-narrative level and a narrative one. The non-narrative level is anytime a writer or artist steps outside of their pre-conceived genre notion is incredibly interesting to me. We're much more familiar with genre writers trying to enter into a non-genre world, even if it's still fiction, like Stephen King or J.K. Rowling writing a straight-ahead book. That, we fundamentally accept, because "genre writers are looking for some cred." But what we almost never see is what Tom did, which would be the equivalent of David Simon saying, "I'm doing a vampire show." We would all go, "Holy shit! He's what?" Or Sorkin. So that idea, just on a fundamental level, reading the New York Times Book Review, Stephen King writing about Tom Perrotta's genre novel. As much as you can have those moments in your life where the the road ahead becomes very clear, and illuminated, and you go, "This feels like I need to be a part of this."

And then I read the book. First off, the idea that it was presenting this huge mystery, the Departure, it felt to me about 50 pages in, "Oh, he's not interested at all in answering what the Departure was. This is just all about the condition of living in a post-Departure world." And that to me became really fundamentally interesting. It's like reading "The Road," where when they get to the ocean, it's not like there's going to be a party, and the sun's going to come out and there's going to be an abundance of food. They're just moving for moving's sake. And as gritty and as despairing and as upsetting as that is, that's what Cormac McCarthy is telling me I'm going to get. That, to me, was very fascinating — to be unapologetic about saying, "This book is about characters living in an ambiguous space where the mystery is not going to be resolved." For whatever reason in my life at that time, I was like, "Good for them! This is what this should be." Because if this was about Joe Fiennes trying to get to the bottom of the Departure, I wouldn't be interested in it at all.

And then I just started — and I've said this to Tom, and I'm not saying this for the sake of our interview — crying, multiple times. And I don't do that when I'm reading. But I just felt emotionally affected and connected to this thing. I can't really explain to you why. It just touched me. I very rarely have an emotional experience reading a book, but I did here.

Alan Sepinwall has been reviewing television since the mid-'90s, first for Tony Soprano's hometown paper, The Star-Ledger, and now for HitFix. His new book, "TV (The Book)" about the 100 greatest shows of all time, is available now. He can be reached at sepinwall@hitfix.com