Perambulatory writing … Robert Macfarlane. Photograph: Rex FeaturesRobert Macfarlane's The Old Ways records 15 journeys – two in sailing boats across the Hebridean Sea, the rest on foot – undertaken by the author. He goes where others have once gone, both geographically and textually. He takes old tracks and rediscovers an old genre of British literature – not so much "nature writing" as perambulatory writing: a type of descriptive text that follows the path of a walker. In English literature this idea of writing-as-walking was pioneered by poets in the late 18th century. In the 1760s, Oliver Goldsmith turned his footsore wandering across Europe into a best-selling poem, "The Traveller". "My prime of life in wandering spent and care / Impelled, with steps unceasing, to pursue / Some fleeting good, that mocks me with the view". The melancholy William Cowper wrote "The Task", two of whose books, "The Winter Morning Walk" and "The Winter Walk at Noon", "retrace / (As in a map the voyager his course) / The windings of my way through many years". To ruminate poetically and to walk became synonymous.
When you walk down a path, someone has been there before you. As well as being rich in natural description, The Old Ways is a bookish book and invokes many literary precedents for its attempts not merely to describe the journeys that the author has undertaken but to re-experience them. So Macfarlane will narrate not only what he saw and heard, but also what he thought as he walked. Sometimes this means historical speculation or geological explanation; sometimes, as in his account of a long walk over the Cairngorm massif, it is something more personal: a string of memories of his grandfather, who lived his last years among the same mountains. In every case, narrative moves to the rhythm of journeying.
Macfarlane's title signals that he has gone back to routes – and implicitly a rhythm of experience and observation – that have some ancient hold on human beings. He frequently insists that walking a path can be a way of returning to the past. For the greatest of all English literary walkers, William Wordsworth, this was an autobiographical imperative. Near the beginning of The Old Ways, Macfarlane cites Thomas De Quincey's estimate that Wordsworth walked 180,000 miles in the course of a long life. (In contrast, but hardly competition, Macfarlane thinks that he might have managed 8,000.) Wordsworth's greatest poem, his autobiographical epic The Prelude, begins with a walk on a lakeland hillside and includes several other closely described walks, including an extraordinary "variegated journey step by step" across France and the Alps.
Wordsworth composed in verse as he walked, reciting and then remembering; writing it down only came later. Macfarlane invokes "the compact between writing and walking". His hero, the early 20th-century poet Edward Thomas, seems to have done the same. "In Thomas's imagination, text and landscape overlap". Macfarlane must have taken notebooks with him, for though his prose may be called "poetic", it is prose still, and relies on an accumulation of sharp particulars that must often have been immediately recorded. "A rainless gale rushing out of the east, deer tracks in moor mud, a black sky, gannets showing white as flares above the sea. Dawn on the Atlantic coast of the Isle of Lewis. Thin light, cold and watery." The verbless sentences are characteristic, the first job of his narrative being simply to set down what was of the moment. (The book is as attentive to meteorology as to landscape, and even offers an index to the different kinds of weather it covers.)
Macfarlane has a special diction for the quiddities of weather and landscape. A glossary at the end of his book explains terms such as albedo ("The proportion of light reflected from a surface") or serac ("A bulging tower of ice on a glacier"), but does not reach to the verbs and adjectives he digs up for the effects of sound or light: yabber, jabbly, sintering, bermed, moshed. He enjoys collecting odd terms of topography from the Hebrides or the Himalayas, as if they were geological samples that he has carried home as evidence of where he has been and what he can remember.
Some of his figurative language has a precision that allows anyone to see what he is describing, as when a heron takes off, "a foldaway construction of struts and canvas, snapping and locking itself into shape just in time to keep airborne". But often his distinctive similes are both highly specific and teasing. Some British readers will surely be perplexed to hear of a tern beating upwind, "its movement within the air veery and unpredictable as a pitcher's knuckle-ball". When he tells us that water in a pool "shone black and thick as lithography ink", or that he saw "billows of rain like candle-blacking dropped into water", do we immediately see what he has seen? What colour is something "dark as mafic glass"? It is as if the writer must prefer the precise analogy to the likeness that we might easily share. You might take the same walk, but you will not see the same thing.
• To order The Old Ways for £5.39 with free UK p&p call Guardian book service on 0330 333 6846 or go to guardianbookshop.co.uk. Robert Macfarlane will be at the Guardian book club on 29 July at Kings Place, 90 York Way, London N1. Tickets: £9.50 online/ £11.50 from the box office. kingsplace.co.uk.
