Joshua Ferris's first novel, Then We Came to the End, a satire of life in a Chicago advertising agency, was an international bestseller and announced him as an authentic voice of his generation. His third book, To Rise Again at a Decent Hour, is about to be published. He lives in New York.

Your novels are fascinated by the strange world of work. In your new book, your main character is a dentist. You seem well-versed in the mechanics of dentistry. How did that come about?
I watched a lot of YouTube. There are dentistry sites designed to help dentists who may not have the resources of the developed world. These sites are trying to help anyone who needs help. And I guess that includes novelists.

I think Martin Amis, a writer famously in thrall to his teeth, once said "our mouths are where we live". What made you want to dwell there in this book?
The starting point was the desire to put people in a small space together and see how they interacted. It was a challenge, how would I imagine a dental office? And how would it inform my characters' sense of alienation and connection. Very quickly on the heels of that there was a lot of thought about rot and decay and death. I wanted some questions that went to the bone of existence quickly and the dental office seemed a perfect opportunity for that.

It feels very much a mid-life book. You are approaching 40 yourself; is that with some trepidation?
Not particularly; unlike my narrator I'm a fairly content kind of guy. I get up and try to use the day in a useful way and try not to think too much about the abyss.

Your writing explores, with great comedy and poignancy, how such contentment is hard-won and easily lost. Do you feel that fragility keenly?
So much so. It's terrifying. That fragility is the substance of all of my bright-eyed 3am reveries.

You describe yourself as an insomniac. Do you write when you can't sleep?
I will get up, write and wonder why I'm writing, and after a while that acts as quite a good way of getting back to sleep.

Does a lot of that half-awake anxiety make its way into the books?
I think so. I wanted in this book to examine the relationship between the main character and the more terrifying aspects of his existence: desertion, religious despair. Those kinds of things were as prominent in my mind as the more traditional drama of what happens between the characters.

Is there a God-shaped hole in your own life?
Yes. The general impression of Americans is that we're all believers. But there are quite a few of us, obviously, across the vast swath of this crazy country who don't have a God. I think of myself, like my character in the book, as a "non-practising atheist". At the witching hour there is a hell of lot to say for divine comfort. I feel excluded from that. There are some aspects of religion – its community, its certainty – that I long for.

Part of your plot takes the character back, through a faked online identity, to the Old Testament. What was the experience of immersing yourself in those verses?
Well, I gained a lot of respect for the Bible. I never knew it first-hand before. The best stories there remove all inessentials, and what you're left with is something extremely efficient. It's almost like a divinely inspired Hemingway writing in those parts.

The internet in the book is often seen as a conversely destructive force. Is that your experience?
I think it's a force of anxiety. Anyone who wants to be completely sure of their information – personal, political, historical – is faced with a huge number of sources willing to provide it. It can be a very dubious place. A hall of mirrors with diminishing returns.

Have you made a conscious effort to block out some of that information when you are writing?
I don't belong to social media at all. Not for any principled reason, but because I don't want to spend the time on it. I do think books are harder to read when you move away from the quick cuts of the internet. You have to reach back for your attention span. If you've spent two hours looking at 6,000 very different web pages it's difficult to concentrate on a single story that requires sustained attention. I don't think books are going to go away. I think maybe they're going to become a more fine taste.

Do you think the pervasiveness of that screen culture also makes novels harder to write?
Not if the novelist is a novelist. The determined novelist is just interested in the fact that she must write novels.

Where did that compulsion begin in yourself?
You would have to burrow down to some substrata of my material existence to find the answer to that one. I started writing when I was seven or eight. It has always been there. I wanted to hear stories, and I wanted to write then. I would repeatedly ask for books to be read to me again and again.

Was it a bookish home?
My parents weren't that bookish, but they were devoted readers to me. It was like: books, they will make you smart and good. And I thought, well this is the world and took it from there.

Your own books are quite distinct from each other. Are you conscious of writing against yourself, particularly after the great success of your first novel?
If I were canny about the whole thing, I would have tried to copy the first success, I suppose. Why not go for the royalties and fame? But I think each new book has to be a repudiation of the previous book. You've been stuck with this thing for three or four years and you are sick of it. You want to fly free and explore something else.

Are you doubtful along the way that it will happen again?
Sure. Unless you're a great prodigy you don't spring into the world with a novel. I have no idea where it comes from so I don't know how to replenish it. It feels in each case, from my point of view, like an attempt to totally re-engineer the world. And to guarantee that you are still in it.

You got out of offices quite early, and lived to tell the tale. Do you ever miss the structure they offer?
I think writing allows for huge inefficiencies. If you're in an office you are inefficient but you're always aware there is someone who wants to eliminate those inefficiencies. Because I am my own boss I don't worry too much. I know I should be acting like an adult, but I can act like a four-year-old. Fortunately I don't mind that at all…

To Rise Again at a Decent Hour is published by Viking on 5 June, £16.99. To buy it for £13.59 with free UK p&p call 0330 333 6846 or go to guardianbookshop.co.uk