In a late lecture Matthew Arnold declared, 'I am returning...to a field where work of the most important kind has now to be done, though indirectly, for religion.' Indirectly, because belief could no longer be communicated persuasively by the old means. A different mode of eloquence was called for, subtle and popular at the same time. 'I am persuaded that the transformation of religion, which is essential for its perpetuance, can be accomplished only by carrying the qualities of flexibility, perceptiveness and judgement, which are the best fruits of letters, to whole classes of the community which now know nothing of them, and by procuring the application of those qualities to matters where they are never applied now.' Essential religion, stripped of godhead and institutional trappings, might be reinvested in - literature, and poetry in particular. Its language could be made impervious to the claims of science and analytical philosophy and to the simplifications of fundamentalism. Poetry could become a hotel for the transcendent, or a bourse in which spiritual transactions might occur. As God disappeared from the space He had occupied, He might find what David Jones called 'His manifold lurking places' in things gratuitously made. The word 'gratuitous' rediscovered its origins in the word 'grace'.

Thus poetry became (again) useful. For many leading poets in the latter half of the nineteenth and early twentieth century, it was an instrument, though its instrumentality was veiled. One task of Modernism was to deliver poetry from such use back to itself. Yet when Arnold, Hopkins and Hardy, in different ways, made poetry instrumental, they seemed to make it more relevant, spiritually and philosophically important, against the grain of the decadents, and against the aesthetic movements which thrived on the incensed fringes of the Oxford Movement and its aftermaths.

Chaucer had the chronological courtesy to die in 1400 and Dryden in 1700, putting down convenient markers. They were unusually obliging. Literary history has gone out of chronological kilter, though literary taxonomists revert to a rough century template. We might agree that the 'nineteenth century' began in 1798 with the publication of Lyrical Ballads, though would we concur on its ending? The death of Hardy in 1928? Or Kipling's in 1936? Or Arnold's in 1888? The twentieth century, some might say, started in 1917 with Prufrock and Other Observations and ended with the atoning line, 'To be men not destroyers', which would have concluded Pound's Cantos had they been concludable. Are centuries getting shorter?

Tearing off the last day of the calendar of the expiring millennium, literary journalists held their breath for - what? It is too early to say for sure. Beyond the phalanx of anthologies and the rhetoric of 'new beginnings', nothing has happened yet. But in criticism it has. One book seems to answer the critical if not the creative moment. Just as Arnold assigned to poetry an instrumental rôle which redignified it even as it called it into the service of a cause, so this new book proposes a mission.

It is published not by an academic press but by Picador, renowned for a commitment to innovative literature; and it is 'about the capacity of the writer to restore us to the earth which is our home'. Jonathan Bate's The Song of the Earth is, as the Mahlerian title implies, elegiac because what we have in literature is residue. It can be reconstituted, but in imagination rather than in fact. Bate is under no political illusions; he recognises how far from environmental action the literary arts are, though they can have ecological consequences. He does not forget how late in the history of our exploitation of the planet he is writing. He is wary of green extremes that issue in the eco-fascism of those who entertain alarming Malthusian notions of population control, and the simplifications of others who appropriate texts with disregard for - or ignorance of - their wider sense.

The book is millennial in a number of ways. It introduces new 'theoretical' readings and will effect a change in the canon we read and teach. It proposes a relevance in the texts it chooses, especially from the nineteenth and twentieth centuries, but also from Shakespeare (hardly a surprise, given that Bate wrote The Genius of Shakespeare) which may have little to do with the authors' original intentions. It would be reductive to call The Song of the Earth 'green', yet that is one of the things that it is. God was dying but he lived on in poetry; Nature is dying, and yet we experience its survival in poetry.

We were sad to learn of the death in New Zealand earlier this year of John Needham, one of PNR's most penetrating essayists. A decade ago he declared: 'one of the key mistakes of twentieth-century literary criticism has been to separate verbal ambiguity from narrative suspense'. Empson said Imagist poetry, with its principle of juxtaposition, forfeited narrative, or movement in time. He then elaborated a theory of ambiguity which introduced points of stasis and suspension within a text, stilling narrative in another way. His critical and poetic heirs, focusing on local felicities, have been tripping over Empson ever since.

With an eye on syntax, on enjambement and its play against syntactical closure, and an ear attuned to rhythmic patterns and variations, Needham set off to test his observation against poems, landscapes and theories. He went looking for John Portman's Westin Bonaventure, the Los Angeles hotel and shopping complex which Frederic Jameson makes so much of in Post-modernism. Would the building, as Jameson suggested, undermine and alter our perception of space? As he moved through Portman's structure and Jameson's essay, things began to fall into place, not least the ways in which theory dates, how it can misrepresent or misconstruct what is really - not 'really' - there.

By plane, boat, car and on foot Needham made his way around the world, discovering whether theory matched up to the things it theorised and to the experience of an actual man in an actual physical space. The essays, published in PN Review, attest to something valuable: the centrality of the human and the humane in modern literature and life. His 1999 book of essays, The Departure Lounge, is another millennial marker, an end and a beginning. In his last essay, 'Of Arteries and Images' (PNR 125, not included in his book), he talks of 'the principle of integration'. That is what his quest, and Jonathan Bate's, is about.