Reeling in the years: Andrew Greig on Norman MacCaig

• Andrew Greig's new book is a homage to his mentor, Norman MacCaig (pictured)

PICTURE, if you will, Andrew Greig and Norman MacCaig in MacCaig's living room in Edinburgh's Leamington Terrace. It's early summer 1995. MacCaig is frail, but feisty. Talk is talked. Whisky is taken. At some point, Greig asks MacCaig: "What is your favourite place in the world?"

"Assynt," the older poet replies, with typical economy. No surprises there. It was his home-from-home; his poetry – especially the later work – is suffused with it. Rarely has a poet written so much about one place. "I know it's Assynt," Greig persists, gently. "Where in Assynt?"

There is long pause, then MacCaig says: "I think it has to be the Loch of the Green Corrie. Only it's not called that. But if you go to Lochinver and ask for a man called Norman MacAskill, if he likes you he may tell you where it is.

"I should very much like you to fish for me there," he goes on. "If you catch trout, I shall be delighted. And if you do not, then looking down from a place in which I do not believe, I shall be most amused."

It was both a challenge and a tease. "It's classic MacCaig," says Greig, talking in his own Edinburgh flat 15 years later. "Playing with you as you might with a fish. 'If he likes you.' It was an irresistible quest. I love a quest narrative, particularly outdoors. Most of my books are quest narratives. I thought, I'm going to have to do this."

MacCaig died the following January, and a handful of years later, Greig headed for Assynt with two friends – "better fishermen, so we'd have a better chance". Norman MacAskill liked him enough to make a mark on a map. They took their tents and fishing rods and headed into the hills for three days. He wrote a feature for this newspaper. And that was it.

Only it wasn't. Ten years later, in the shed in his Edinburgh garden in which he writes, he found his memory returning to Assynt. He looked out his journals from the time, laid the photographs out on the desk. The Loch of the Green Corrie became a portal into unfolding memories.

"There was a feeling that I haven't done with this, it hasn't done with me yet," says Greig, 58, a highly acclaimed writer of fiction, non-fiction and poetry. "I realised that in the first place I went for Norman, but it had now become my own quest. It was like looking at a series of Russian dolls: reflecting on the trip ten years ago, then back on when I first met Norman, and on his memories of Assynt through his poems. Over ten years, it matured, parts of it acquired more meaning." It started to turn into a book.

At The Loch of the Green Corrie is a hard book to categorise. In the same way that his 2006 book Preferred Lies was ostensibly about golf, but was more about his recovery from a life-threatening brain illness, it is not really about fishing. It's part-memoir, part-outdoors book, part collection of essays. Painfully honest, beautifully written, it is a writer's way of processing the world.

Taking its structure from the angler's rhythm of cast-and-retrieve, it also has something of an angler's spirit. After all, fishing is often not about what you catch. "In fact, you tend to put it back. I think the fishing is almost an excuse for being there. It connects you to where you are in a way that simple sightseeing doesn't, it attunes you to the wildness of nature. It's about putting the time in, a bit like writing. You turn up in the shed and you do the thing until lunchtime, it's the thing that happens round about that's interesting."

It is a book full of people, alive and dead, but the abiding presence is MacCaig himself. "Going to Assynt is like being inside Norman's skull, everywhere I look I see it through the eyes of the poems. You could do a MacCaig trail. You can find that very thorn bush he wrote about, that rowan tree."

Greig was a teenager when he first climbed the tenements stairs at Leamington Terrace. Having read MacCaig's poems in The Scotsman, he sent the poet some of his own, then, at his invitation, caught the bus from Anstruther to see him.

"I knew as soon as I saw the poems in his hand I'd made a terrible mistake," he grimaces. "He said: 'I quite like some of these poems, but then I would because some of them are quite like mine.' Pause. 'Perhaps you should write some like your own.' I felt hopelessly abased and apologetic, but when I thought about it more, I realised it was cutting, it was true, but it was also extremely generous. He wasn't looking for disciples."

He continued to visit MacCaig as his own career took shape; poetry was followed by two books on mountaineering, and later by acclaimed novels like Electric Brae and In Another Light. The older poet wrote references for grant applications, occasionally provided "simple, clear, gnomic" suggestions about poems.

For the writers of Greig's generation – Liz Lochhead, Ron Butlin, Brian McCabe – MacCaig was a link to the generation before, who had in their turn drunk whisky in Leamington Terrace: Robert Garioch, Hamish Henderson, Sorley MacLean, Iain Crichton Smith, George Mackay Brown. "The book became, in part, a homage to that group of people, how they conducted themselves and taught us to conduct ourselves. They made it clear there was room at the bar of Scottish literature, if you meant it and weren't going to get self-important.

"I'd never call myself an intimate friend of MacCaig, but he was a role model, a mentor. I liked him, he really mattered to me, and as the years went on after his death, I increasingly missed him and thought about him."

When Greig returned to Assynt, this time with a book in mind, he tracked down some of MacCaig's old friends, and began to discover another side to the poet. In Assynt, MacCaig the writer and schoolteacher was off duty. Rare photographs show him in long shorts heading off to fish the hill lochs with his friends AK MacLeod (a consummate poacher) and Charlie Ross (the local gamekeeper). It was a time of whisky drinking, conviviality, fishing and friendship. Stories abound. "At one point they had an illicit still together," says Greig. "They were like mischievous wee boys."

When AK MacLeod died in 1976, MacCaig wrote a series of beautiful elegies, the only time he wrote a group of poems for the same individual. Greig believes they are some of his finest work, and shed an important light on the man who is thought of as a poet of birds and frogs, by his own account "easy-osy and jocose".

"The elegies celebrate the wonder of being alive, but they're increasingly ringed around by darkness and grieving. I loved the honesty of that, he never said death is all part of life, it was always 'that obscene death'. He was increasingly registering the undo-ability of death, not just your own, but of people you care about. Most of his best stuff is full of grief."

It chimes with Greig's own feelings since his recovery from a life-threatening colloid cyst in 1999. After the illness, he found that he experienced life both as more vivid and more fragile. He was viscerally aware of mortality, his own and that of others. "That was one of the things which connected me with Norman. All that makes sense to me in a way it didn't when I was reading these poems at 17, 25, 30. That's what sparked off many of these memories."

It may also be the reason why this book is his most personal to date. He writes with fragile honesty about his mistakes, his relationships, and about the breakdown he had as a young man, after which he spent time in hospital. "I just felt it was time (to write about it).

'Stock-taking' is too cold a phrase, but it did seem to be necessary to re-live or re-understand. I write about things, that's what I do, bring them out into the open, into the light of day. In time, things take on a different light altogether."

In At The Loch of the Green Corrie, he balances the personal with the impersonal: essays about Assynt's unique geology, the successful crofters' buy-out in the area, about ideas of Scottishness, highland and lowland, East Coast and West Coast.

And then there are interludes of joyous anecdote, such as the accounts of his time as a wannabe singer-songwriter in the early 1970s, when he and his bandmate caught the fish lorry from Anstruther to Soho and washed up in the offices of the legendary Joe Boyd of Witchseason Productions, the man behind Nick Drake, Fairport Convention and the Incredible String Band.

"He was so kind to these fish-smelling Fife boys. We arrived fainting with hunger, he took us out for a bit of breakfast, listened to our dicey tapes, and said: 'Yeah, let me know what you do next'.

"I could have written a whole book about that time. We met John Martyn in the street – he was the nephew of our gym teacher from Fife – and he asked if we wanted to go on and play before him – so we did. And there was one day when Nick Drake came in to see Joe. We didn't know he was going to kill himself and then become a legend, he was just this guy who looked at his feet all the time."

In time, he reconciled himself to a career as a poet. "I think it was when I got my second book of poems, Men on Ice, published, I thought 'Hang on, I've never got a single song recorded in eight years, but I've got two books of poetry out, I'll stick to what I can do.' I didn't feel bad about that."

He still plays music for fun, he says. In the next room there is a banjo, a guitar and a clarsach, which he's learning. "A lot of writers are failed musicians. When I'm in Orkney I play with friends. Very occasionally I get paid 30 for working myself to death in a pub, shouting myself hoarse. And it's great!"

• At the Loch of the Green Corrie, by Andrew Greig, is published by Quercus, priced 16.99.