David Szalay, 51, grew up in London and now lives in Vienna with his wife, having previously moved in 2009 to Hungary, his father’s birthplace. In 2016 he was shortlisted for the Booker prize with his fourth novel, All That Man Is, nine separate stories “self-assembled in the reader’s mind into a sort of collage-novel” (London Review of Books). His new novel, Flesh, follows the fluctuating fortunes of a young Hungarian ex-convict who makes his life in the UK after serving in Iraq.

Tell us how Flesh came to be.
I decided to abandon a book I’d started in 2017. It just wasn’t working, so it felt like a weight off my shoulders; nevertheless, I was under contract and had to come up with something. Literally nothing in Flesh is directly autobiographical, but it started with my underlying experience of being poised between two places and feeling not 100% at home in either of them. I no longer really feel like a native of London, but nor do I feel entirely Hungarian. Even for the decades I lived in London, just by virtue of the name that I have, there was always a sense of being... outsider is too strong a word; I was more of an outsider in Hungary, certainly, but a kind of insider-outsider, because I come from a Hungarian background but don’t speak Hungarian very well. That sort of grey zone interests me.

The novel implies that all the tumult of the protagonist’s life begins with the shock of puberty. What made you want to dramatise that idea?
My aim was to try to be as honest as possible about what it’s actually like to be a male body in the world – to be a body that has its own demands, and how you manage, accommodate, satisfy and fail to satisfy those demands, and what experiences that leads you into.

Money is pivotal to the story, as it tends to be in your work.
It structures our society in a deep way. I say that as someone who’s not Marxist or anything like that; anyone can see that money exists as a way of distributing power. The need for money, or wanting more money, or just sort of having to have money, is central in all our lives. Often it’s underplayed in the same way as physical experience – a bigger part of our existence than you’d think from reading fiction.

In form and style, Flesh resembles Turbulence [2018] and All That Man Is, which seemed to mark a break from your first three novels.
With my earlier books, I was doing something completely different after each one. Looking back, that was born out of not yet having found what really works for me. I enjoy books made of free-standing units of writing that are somehow in dialogue with one another, where what happens in the gaps is as important as the chapters themselves. The way that the reader has to do their own imaginative work means they might come away with a sense of having read a book that covers a large amount of human experience, without having to plough through a 1,000-page 19th-century novel. I don’t think anyone’s seriously going to deny that we live in an era of short attention spans, which probably isn’t good, but we’re going to have to work with it the best we can.

Where do you write?
For various family reasons I go back very frequently to Hungary, so I have to be pragmatic – it’s not like I have some holy desk that’s the only place where I can do anything. One challenge is always to hold on to the reality of the fictional world for it not to seem like a silly story I’m making up. The hour immediately after waking, with the phone still switched off, is when that world can seem most real.

How come you left London?
I didn’t know I was leaving! I went to Hungary planning to spend a few months and ended up there for more than 10 years. One of the things that kept me in Hungary, unquestionably, was that I could afford to live on my income from writing, which was then very meagre indeed, in a way that I simply wouldn’t have been able to in England.

What first led you to write fiction?
I genuinely don’t know [laughs]. I’ve been writing for pleasure since I was very young; I stopped in my 20s but came back to it. The thing that got me hooked at the age of 10 or something was probably the game of it – to master the way a book manipulates the reader. I don’t mean it to sound sinister; it’s just the game that’s going on all the time between writer and reader in every context. As a child I enjoyed that and quite unselfconsciously wanted to try doing it as a writer.

Is there anything you recall reading at that time?
I enjoyed The Hobbit but found The Lord of the Rings very boring. I remember reading books that were slightly unexpected: at 12, I read the complete works of Frederick Forsyth and really enjoyed them, probably much more than I would now. It’s interesting [thinking back] – they work very much on close control of the reader’s expectations.

Name something you need in order to write.
Solitude. I find the heavy lifting near the beginning, where you have to imagine a world out of nothing, easier if I can go away and basically not interact with anyone. More than a week and it starts to become oppressive, but a week of solitude can be very useful.

The story goes that in 2016 you came within a hair’s breadth of winning the Booker. Do you ever think what might have been?
Of course. Just being shortlisted transformed my career – I sold far more books than I did before – but it was very disappointing at the time. If I’d won, maybe I’d have become lazy. It feels like some big peak to come back from; more prosaically, you probably get enough sales generated that you don’t have to publish for some years. Either way I’ve managed to convince myself that not winning was a good thing.

• Flesh is published on 6 March by Jonathan Cape (£18.99). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply