Paul Murray’s T-shirt, a bit like himself, is a study of optimism. Dublin is only newly out of the ice and snow to which it was so unaccustomed, and Murray’s faded blue T-shirt depicts a pair of sunglasses and the words “beach house”. Mortified at being late for the interview - he’s not late, there has been a mix-up about the meeting point - he arrives in a blur of shock-headed hair and apologies.

Murray’s second novel, Skippy Dies, a thumping 660-pager sure to be a cult read, is published this week. His much-praised first novel, An Evening of Long Goodbyes, came out in 2003 and was shortlisted both for the Whitbread first novel award and the Kerry Ingredients book of the year. Skippy Dies is a multi-stranded comic satire about life in Seabrook College for Boys in Dublin; an institution that sounds similar to a well-known private school for boys in south county Dublin.

Skippy Dies  was seven years in the writing, and originally ran to more than 1,000 pages. He wrote it all in longhand, and thus lost track of its length. “I didn’t know how long it had got until I typed it up,” he confesses, a little sheepishly, staring down at his coffee. “I’ve always been attracted to the book-as-world. But it wasn’t working as a 1,200-page book. The story was getting lost. It was 320,000 words, something like that. It took a long time to winnow it; to find the story in the midst of all the verbiage.”

Authors are, by definition, fluent with language. Not many of them include words such as “verbiage” so casually into conversation. Murray (34) is clearly both smart and well-read, throughout the interview unselfconsciously quoting at length a range of heavyweight writers: Samuel Beckett, Thomas Pynchon, Salman Rushdie, William Gaddis. And it is unselfconscious. There is the sense that he thinks often and seriously about the craft of writing, carefully turning over the works and thoughts of his favourite writers like sea-washed pebbles in his head, trying to figure out how they got it right.

Murray is that rare, old-fashioned interviewee; as an author, he would clearly rather talk about his novel than the person who wrote it. “I’m a big fan of Thomas Pynchon and I really like the idea of authorial anonymity, a kind of separation being maintained between the writer and the work. I like the idea of the purity of the book just being considered by itself. But I don’t think you can do that any more. You have to put yourself out there now,” Murray says reluctantly when asked to talk a little about his background.

Pushed, he baldly summarises his life to date in six short sentences. “I’m from Killiney. I went to school in Blackrock College. I went to Trinity and did English and philosophy there. Then I did the Masters in creative writing in UEA. I got the two-book deal shortly after I finished that, which was really lucky. And that’s what I’ve being doing since.”

While at Trinity, Murray repeatedly applied for the creative writing course offered there. “A friend and I would apply for this course and we’d get rejected every year. And in the fourth year, we both finally got in. Deirdre Madden was doing it that year, and she was really encouraging. People liked the stuff I was submitting; I’d never shown my work to anyone before.”

Between graduating from Trinity and doing the creative writing masters at UEA, he worked for a short time in Barcelona, teaching English. This was at the end of the 1990s. His subject has always been Dublin, and he swiftly noticed the changes that had happened in his home city during his absence. “When I came back from Barcelona, suddenly everyone had mobile phones. Nobody had one when I left. Prior to that, mobile phones had been real objects of derision. It was still a status symbol back then, but it become a status symbol that everyone had.

“I got a job in a café in the Westbury Mall and they had panini, and focaccias, and ciabatta, and they had cappuccinos and lattes. People would look at the menu and say to me',what’s a ciabatta? What’s a panini? What’s a latte?’ and I’d say, I’ll go and ask chef. The changes were very sudden. This aspirational culture arrived very quickly.”

When Murray moved to work in Waterstone’s, John Boyne - later to publish the hugely successful Boy in the Striped Pyjamas - was also working there. “He read a chapter of my book, and he was really, really encouraging. You sort of feel writing is a pie-in-the-sky aspiration to have. I’d written all the time, but I’d never believed it would translate into a career.” Boyne had been to the UEA, and on his encouragement, Murray applied for, and got a place on the course. Andrew Motion was at that time head of the department.

“It was difficult in that there was only one class a week, and most people lived in London or Cambridge, so I didn’t see them often, because I lived on campus. It was a really lonely time. My girlfriend was back in Dublin, and it was a 45-minute walk into Norwich town. The university was built in the 1960s, a type of Brutalist architecture, so you feel like you’re a little mouse in a concrete maze.

“Writing courses are really hard and kind of depressing, but I did make some friends there. There were 24 aspiring writers in my year, all with no money, all competing with each other, so there was a bit of, um, scrapping.”

So what happens to a writer when a book takes seven years to write, and the advance is spread thin as a result? “The money problem,” Murray sighs, and starts speaking with confidence and optimism.

“Jay-Z was talking about music downloading, and is music downloading killing the industry, and he said one effect of the music downloading boom is that only people who are really, really committed to music will actually stay in it. People who aren’t in it to make money will be the folks who stick it out and find some way to make it work. So maybe it’s not entirely a bad thing that there’s so little money in writing because it means that the folks who do it are the folks who are committed to it.” And he sounds as if he really believes that.