It was April 1988, and yet again Seamus Heaney submitted himself to lionising by the London literati. He had flown from Harvard, where he was teaching, to collect his latest literary prize (seven years before the Nobel laurels), the Sunday Times award for excellence in writing. To the quiet astonishment of the assembled guests (including myself) Heaney made an acceptance speech more overtly political than ever before. Instead of modest disclaimers about fame or reflections on the role of the poet, he talked about the Anglo-Irish agreement and offered some trenchant thoughts for Margaret Thatcher on the crisis in Ireland. Unprepared, nobody took a note. There was no copy of his speech to circulate. The lion cuffed literary complacency with a velvet paw.

Looking back it is easy to see that he was liberated by absence. As the Irish writer and broadcaster W.R.Rodgers once said:“There is for Irishmen a need to distance themselves ... to turn a telescope on their own country.” Then in his middle age, the “50-year-old smiling, public man” had already experienced early success, the envy of his peers, pressure to shackle his poetry to the republican cause, and the questioning critical backlash that always, inevitably, balances deserved hyperbole.

The constant praise of the “best-Irish-poet-since-Yeats” type made him squirm. He sat poised on a pivot, a one-man dialectic in whom opposites co-existed: Ulster v Eire, English learning v Irish culture, education v “the language of the tribe”, debate and opinion v “the government of the tongue”, dogma v liberalism, belonging and “society” v the inevitable loneliness and exile of the soul. In 1984 he told me (in an interview for The Times): “The inner place of your first being is a large, solitary gazing-out at the world.” The evidence of his last volume, District and Circle, is that the gravitational pull of the poet's gaze still seeks “to restore something to yourself” - in a phrase from this rich volume.

First suggested by the interlocutor to Heaney in 2001, Stepping Stones is a series of questing journeys, looping and revisiting, explaining and analysing - based on “written questions and observations” that Heaney would reply to as he wanted, adding and omitting at will. The result is a Heaney word horde that will not be surpassed for some time, and surely places Dennis O'Driscoll in prime position to write the authorised biography that must come one day. In an important sense this form - the colloquy - becomes a version of autobiography. Stepping Stones will be seized on by students of the work as well as the common reader, offering not individual exegesis (Heaney made that a condition of his agreement) but stories behind many of the poems that enlighten as well as delight. The subtitle is, in a sense, misleading, since “interview” suggests a transcript of something recorded, with all the colloquialism, hesitation and circumlocution that that implies. Yet the series of interviews that combine to form this elegant tour of a poet's mind and art are genuine collaborations: Heaney's biography appears beneath O'Driscoll's on the back flap.

O'Driscoll, himself a fine poet and critic who knows the price Heaney pays for celebrity as well as the toll it has taken on his health, wanted to create a volume that “would be a substantial addition to his oeuvre rather than merely a subtraction and a distraction”. He questioned Heaney about his childhood, student days, marriage, and so on - all of which Heaney has written about extensively, yet here we find more detail, more “pictures”. It is fascinating to witness the apotheosis of this creative exchange in off-shoots of the conversations honed (in District and Circle) as both poems and “found prose”.

The bulk of the book consists of revelatory chapters on the individual volumes of poetry as well as insight into Heaney's literary and artistic influences. It's all vital, pulsing stuff. In the introduction O'Driscoll explains how he and Heaney worked together towards the final text, “reviewing responses, filling gaps, remedying omissions, adding narrative links”. The miracle is that this laborious process should result in pages that read so conversationally, like a true meeting of minds - the erudition and acute sensibility of the questions matched by Heaney's customary virtuoso display of knowledge, insight, and grievous (a favourite word of his) honesty.

The coda of the final chapter is fittingly elegaic, not simply because Heaney reaches 70 next year, but because his poetry has always made its obsequies, reaching towards the “bone dreams” within soil and bog and communing with spirits until, in District and Circle, “I more or less ghostify myself”.

All those years ago, when the formalities were over and friends gathered in a private room, he leant back with pleasure, glass in hand, as his dear friend David Hammond played Irish folk songs on his guitar and Seamus Deane merrily took the floor. Nostalgia beamed in that broad face above the incongruous tuxedo as his countryman's fingers strummed the tunes. That was a glimpse of the real Heaney, steady within himself, rooted in tradition, sharing the sentiment later to be expressed by his friend Czeslaw Milosz: “the desire not to appear as other than I am”. Twenty years later, he is intensely present within these pages - still surprising, still defying “the merciless landscapes” with generosity, courage and joy.Stepping Stones: Interviews with Seamus Heaney by Dennis O'Driscoll

Stepping Stones: Interviews with Seamus Heaney by Dennis O'Driscoll
Faber and Faber, £22.50; 560pp Buy the book

Times Recommends

• The Sunday Times 100 best holiday reads
• What will we be reading this summer: the booksellers predict
• Literary festivals: a survivor’s guide