Light is a lovely subject but also a difficult one. By nature evanescent, it’s intrinsically hard to capture. Ann Wroe has written a wonderful literary meditation on this most elusive of phenomena in Six Facets of Light, moving back and forth between its worldly flicker and the more deeply hidden notion of light in a spiritual sense. Her quest is for lumen and lux alike.

The starting point is a series of walks on the downs and coast between Eastbourne and Shoreham with notebook at the ready. In this sense she belongs to the tradition of ‘walking writers’; some of their observations are woven into her text. Her wanderings are accompanied by a host of witnesses, from writers and painters to a more thinly seeded group of scientists who have tried to define its properties. Wroe’s patterns often describe or parallel the dense interconnective web of the natural world itself.

You could describe the book as a circular walk, with endless paths branching off into the reflections of others. It starts and ends at Eastbourne, reputedly Britain’s sunniest town, where one of the book’s presiding spirits, the painter and engraver Eric Ravilious, grew up and taught. A brilliant collage, starting and ending with the same phrase, “a single yacht…cleaves the sea like a blade.” It’s tempting to see it as a kind of rosary, too, counting off beads of literary wonderment to illuminate the world within.

Companions on the adventure range from Hopkins, Clare and Blake to Coleridge, Wordsworth, Milton, or less elevated folk like Richard Jefferies and Izaak Walton; from Dante and Goethe to Thoreau and Whitman. All are visionary writers, and most are poets. Christian mystics such as Böhme and Eckhart, Henry Vaughan and Thomas Traherne also find their place.

Starting with Ravilious, Wroe’s painterly company embraces Samuel Palmer, Joshua Reynolds and John Constable along with Monet and Van Gogh. The science contingent is a trio of greats – Galileo, Newton, Einstein – and Planck. It’s a formidable cast; yet Wroe wears her learning with a fitting lightness. She draws not simply on well-known published works, but just as often on journals, diaries and letters.

The book is suffused with vivid personal memory and precise, delicate observation of Nature. Wroe’s feeling for landscape is both sensitive and acute; her style is lyrical and precise, full of surprises, and interspersed with observational poems of her own. The writing may seem to meander, but in truth it progresses by flitting from one thing to another in bold associative leaps.

She’s equally good at evoking a mood of near-panic that once took hold in a field of oilseed rape below Firle Beacon, lifted by the sight of stray wild flowers, as evoking quiet lanes, crumbling chalk cliffs, or the myriad kinds of Sussex gate latch. She finds light present in the world around her in the least regarded places – almost everywhere. She learned to read the country as a code when young.

Beginning with the chalk landscape around Eastbourne, she finds chalk spoil is “the uncut ore of light”. This sense of transformation immediately extends to Traherne’s belief that stones were “jewels already”, or Jefferies examining pebbles on Beachy Head, or Clare hunting for shells in Northamptonshire. The humblest part of Nature, she writes, “might hide unexpected reserves of light”.

She tracks its traces in grass, reeds, fruit, and trees such as an old thorn above Lewes or another at Stanmer, thrust, like Joseph of Arimathea’s cane, into the ground to flower. The next chapter applies a visionary treatment to birds, seen “not as heralds of light but as its creators”. Doves, “solid as pieces of domestic chinaware”, make unlikely agents of celestial light, but the poet R.S. Thomas finds himself remembering Coleridge’s thought that birds were “a repetition…of the eternal act of creation”.

Wroe’s next meditation, In the Beginning, initiates its theme with the Book of Genesis. She finds the words “simple and unstinting as the sun above me”. Within a page or two, however, she launches into the reflections of Hermes Trismegistus and Meister Eckhart, pausing to invoke Ravilious seated in “the old Belle Tout lighthouse above Beachy Head”. Then it’s back to Milton and Hopkins and on to the image of spiders weaving gossamer threads of light, ending on Turner and Goethe’s theory of light.

This shuttling and weaving continues throughout the book. Each chapter unfolds from a new point on Wroe’s Sussex itinerary and marks a new pathway of thought. Her looping narrative touches on bread and its heavenly form, manna, on stars, on the exacting and ingenious techniques that artists used to capture it on the surfaces of drawings and paintings, on angels and spirits and saints.

Wroe is keenly aware that for all its miraculous subtleties, light can deceive. She describes it as “cruel, tricking” in a chapter that begins at Birling Gap, recounting the drowned bodies of shipwrecks or suicides. These sadder moments do not linger, for she moves swiftly on to description of a 1790 wreck that left thousands of lemons “strewn on the beach like hard yellow drops of Mediterranean sun”.

After a description of vanished light by a striking image – “silky as Ginger Rogers – or as Venus diving back beneath the waves”– she darts off into an account of Einstein, surmising at 16 that he could run as fast as a beam of light in a vacuum, and later defining the speed of light in the celebrated equation E=mc2. Then she follows it underwater with Coleridge, or onto white walls and paper in pursuit of its animate nature, where Van Gogh and Goethe found it paralysing.

Wroe is obituaries editor of the Economist, and in this book she seems to glory in her liberation from the particulars of lives that reached their end. Previous books include biographies of Pilate and the poet Shelley, while her Orpheus: The Song of Life won the Criticos Prize and delighted readers with its blend of scholarship and imagination. This latest work is a hymn of light, and doubly welcome in a time when the evidence of darkness seems more difficult to avoid.

Hugo Davenport is a freelance journalist.