SPEAKING from Londonbeforehis appearance at the Edinburgh International Book Festival, Nick Laird has not yet selected the poems that he will read aloud to launch his new collection. He hasn't talked or even thought about these poems since he finished them, when he felt "great for about 10 seconds, then a much longer-lasting sense of distaste and shame".

"I think that's how it works," says Laird - for himself and, he suspects, every other poet. On the train up to Edinburgh, he will choose from this latest, second volume, titled On Purpose, the ones that seem "least bad" to him.

"I can't bear to read anything from the first book at all," he says of his debut collection To A Fault, which was published shortly before his debut novel Utterly Monkey in early 2005. To A Fault's contents addressedLaird'sbackgroundandinfluences openly, but with caution. He comes from the Protestant side of Cookstown, County Tyrone, a divided town even by Ulster's standards, and equidistant by only 10 miles between the birthplaces of Seamus Heaney and Paul Muldoon, both of whom were detected as transparent guiding lights in every positive and negative review of the book.

Fair enough, says Laird. "Every poem is in dialogue with every other poem. Northern Irish poets have a heritage which should be inhibiting, but in a way is enabling, because voices like Muldoon's and Heaney's tell you that you have as much stuff to write about as anyone else."

To A Fault was also read closely for references to his best-selling wife, the novelist Zadie Smith, as was his own novel Utterly Monkey, which seemed autobiographical:thestoryofanIrishboy (unhappy, as Laird was, in his postgraduate job at a London law firm) who meets an erudite black English girl. He reminded everyone who asked that the novel was a fiction, and the poems, even those which described a similar marriage to his own, were invented out of "psychodrama".

Both books won awards, and appeared together on the longlist for the inaugural Dylan Thomas prize, but that did not make Laird satisfied with their contents. "With your first book, you're sort of interested in prizes and reviews. Then you realise that the process of writing is your only reward."

This, as Laird knows, might read in print like the "relentless verbal negativity" that one critic identified in his earlier poems, but sounds lighter and better-humoured the way he says it.

He can and will answer a ponderous metaphysical question - using the example of funeral rituals to illustrate his point that "there is something very primal in the connection between spirituality and the sound patterns in poetry" - but not before asking if it's not a bit early in the morning for that kind of talk.

Laird is no less aware than anyone else in his profession of how differently words can work on the page and in the air, and is more interested than most in the "variety" of those effects.

"I couldn't just write a book of sonnets," he says. "I want the shape, sound, form of each poem to reflect the subject matter. The poem has to be the right shape of container for the thought."

On Purpose, as such, contains verses about Holocaustsurvival(Lipstick),dogs(Pug),anda sequence of marital portraits which have militaristic titles (Offensive Strategy, Posture Of Army, Variation In Tactics).

From one subject to the next there is not much uniformity of breath-groups or line-breaks, but patterns do emerge, such as Laird's recurring use of hard science as a "deliberately" secular means of inquiry into powerful emotions.

In Terrain, the poet finds his partner asleep in front of the TV, and remembers reading that some of that static is a product of "cosmic radiation/interfering from the very edge of space and time", while string theory posits that "all the other universes press like lovers up against us".

In a shorter piece, The Perfect Host, it's pointed out that only tears of authentic sadness contain manganese. The New Scientist and neuroscientist Dr Vilayanur Ramachandran have lately become as much muses to him (although he doesn't use that word) as Zadie Smith (although he doesn't mention her name). "I've been wondering how far literature, and especially poetry, can engage with science," he says. "Neuroscience in particular seems to me to be getting closer to the space where philosophy used to be, asking the big questions about how we understand ourselves."

Laird and his wife recently moved to Rome, while their house in London is being underpinned to repair subsidence. They've been unlucky with Italian property too - the first flat they rented, where Smith wrote in the hall and Laird in an airing cupboard, burned down while he was away and she was walking the dog.

"We're not playing the blame game," he says. And if it's "impossible to stay depressed in Rome", it's also impossible, in the city where Keats is buried, for the poet not to think about death. "I've always been like that. I was in a beer garden the other night with a friend, and it was lovely out, but we were still talking about the imminence of our deaths. We couldn't believe that everyone wasn't screaming with their mouths open at the horror of it all."

On Purpose is published by Faber at £9.99. Nick Laird appears at the Edinburgh International Book Festival today at 10.15am