I opened this book of essays with a heavy heart. I was bothered by the coldly abstract cover and the blurb's threats of 'theory', 'polarised debate' and 'liminal spaces', but as I had recently curated an exhibition about border country I felt a duty to read more about borders, 'the most contested and sensitive concepts of our time'. To my relief, this is no clinical dissection but a vivid journey of the mind. Nicholas Murray is a charming, easy, enlivening companion across actual and metaphorical borders. He tells stories, recalls deep knowledge and sparks ideas as we go. The essays trample happily over booksellers' categories of travel, reportage memoir, politics and biography. They visit all sorts of borders along the way - not just of territory but class, political allegiance, sanity, even life and death (he writes a fierce, touching account of an aged friend's 'care pathway' between residential homes and hospitals).

But even his most conceptual borders resound to his appreciation of place - Labour Party schisms are conjured in the meeting halls of 1970s Bermondsey; his journey to depression as a young man was in the hop fields of Kent. When he talks about the boundaries of class, the place is Eton, where he has been invited to speak. He begins this excursion into privilege at the grim border zone of Slough, from whence he is borne up a tree-lined avenue to afternoon tea, enjoys a discussion among exquisitely mannered young men in tailcoats, is entertained to supper and gives his lecture on Aldous Huxley's The Perennial Philosophy to a packed, appreciative audience. Then comes the moment when he transgresses, after all his welcome in this elevated country, by asking hesitantly if there might possibly be a fee. 

He unpacks literary associations wherever he goes. Huxley, whose biography he wrote in 2002, comes to him often, and literary life is always in his luggage. At times he goes on pilgrimage to writers' places - on the Franco-Swiss border at Ferney he considers Voltaire, who found it helpful to skip jurisdictions here when trouble came his way. On the train past Moreton-in-Marsh he hears the birds of Edward Thomas's Adlestrop as counterpoint to the stabbing he has just witnessed in the unexpected setting of a carriage on the Cotswold Line. We meet the ghosts of Kafka, Lawrence, Joyce, Traherne and many more. At St Asaph he writes sadly of the asceticism of Gerard Manley Hopkins, instructed by his Jesuit rector to refuse all study that might bring him enjoyment, including learning Welsh.

Murray, in a way quite alien to me, cherishes the discomforts of the journey as much as the arrival. Heading into the Balkans he write, 'There was the excitement to come of six borders to cross in the next couple of weeks' (though even his spirit is dented eventually by border bureaucrats, corrupt railway officials and armed guards). He is happy to savour the thought-provoking happenstance of detours and discoveries: 'These idle speculations are what travel is all about.' Deep inside China for nine months in the 1980s he recognises that he can never penetrate the life of such a separate culture; nearer the edges as he travels the few miles from Morocco to Ceuta to Gibraltar he sees how proximity diminishes each neighbour.

He does not ignore present anxieties. Though writing before Trump's travel bans and Brexit's threats to movement, he traces tensions that gave birth to both. He asks whether we want a border-free, homogenised globe or a series of compartments where difference is enjoyed. His instinct is for diversity, but he knows that national borders control movement mainly to deny it, excluding people not just on the grounds of nationality but religion, class and wealth. (The contrasting experiences of Muslim refugees and well-heeled foreign bankers show how differently permeable they can be.)

"I want to see fewer borders, more eager coming and going, more sharing of experience, language, culture, being. [...] But not the borderless world, the realisation on earth of globalisation's dream, of life sans frontières.

The route taken through the essays, like his travels, is unpredictable. Twenty-one under the title 'Crossings' ricochet through journeys, visits and themes; then just four reflect on the author's thirty years 'Living in Border Country' in Radnorshire. It's an unnecessary, unequal division - four-fifths to one-fifth - but then what border divides a territory fifty-fifty?

Murray realises that crossing boundaries helps him understand his life, divided as it is, not least between London and Wales. 'I can feel,' he writes, 'and have always felt, that a frontier fence runs through my own self.' He is one of nature's doubters: uncertain, tolerant, exploratory, questioning. These are qualities that make him a good companion and a thoughtful guide to a tense, pied, and complicated world.