Bloom has spent much of his career cultivating ideas that received their definitive early expression in The Anxiety of Influence (1973). That book drew on his intensive study of Romantic poetry, purloining concepts from Nietzsche and Freud to fashion a theory that claimed to account for poetic originality, which Bloom argued was achieved via the individual poet's creative struggle (agon is his technical term) to overcome the powerful and potentially overwhelming influence of an earlier poet. By the time he came to write the best known of his later books, The Western Canon (1994), this quirky psychological-aesthetic understanding was being presented as a comprehensive theory of literary greatness and Bloom was styling himself as a solitary but implacable enemy of all historicised and ideological approaches to literature. As he reaffirms in The Daemon Knows, historicised readings 'cannot account for aesthetic and cognitive splendors. Their contextualizations blur more than they illuminate.'

The Daemon Knows sets out to examine the aesthetic and cognitive splendours of a dozen American writers, who are arranged in pairs so that Bloom might perform comparative readings. There are chapters on Walt Whitman and Herman Melville; Ralph Waldo Emerson and Emily Dickinson; Nathaniel Hawthorne and Henry James; Mark Twain and Robert Frost; Wallace Stevens and T.S. Eliot; William Faulkner and Hart Crane. Though all of these authors have been admitted into Bloom's canon, he stresses that the book is not intended as an exercise in canon formation. Its focus is, rather, the way his twelve subjects achieve a kind of literary sublimity, in that they 'represent our incessant effort to transcend the human without forsaking humanism'.

The concept of the sublime, an aesthetic category given its classical definition by Longinus and revived in the eighteenth century by Edmund Burke and Immanuel Kant, involves a sense of awe at something greater and more powerful than oneself, whether that be God or Nature. Bloom begins The Daemon Knows by noting that there is thus a paradoxical quality to the notion of a 'humanist sublime'. The sublime in literature, he observes, 'has been associated with peak experiences that render a secular version of a theophany'.

Harold Bloom (photograph by Michael Marsland)The specifically American sublime, as Bloom conceives it, sharpens the paradox, since it links the concept to the 'American Adam' or 'God-Man' of the New World. The key figure here is Emerson, who articulated what Bloom refers to as the American religion of self-reliance and 'radically internalized the European sublime'. The subjective implications of this inbent conception become evident in the long opening chapter, in which Bloom insists that Whitman's poetry is fundamentally auto-erotic and reads into the fearful whiteness of Moby Dick 'the trope of the intransigent blank, an ultimate image of our American selfhood'.

Much of the book's peculiarity lies in the fact that, for Bloom, sublimity is experienced not in the encounter with God or Nature, but with the greatest literature: those inexhaustible works in which a writer has achieved a 'breakthrough beyond the reach of art'.  It is on this point that his critical method (such as it is) blurs the distinction between his attempt to formulate a genuine aesthetic of difficulty and irresolution – perhaps best exemplified in his reading of Dickinson's brilliantly unorthodox and ambiguous poetry – and a literary ideal that is frankly evasive. This critical awkwardness is encapsulated in the book's other key concept, the daemonic, which seems to shift uneasily between technical specificity and a kind of wilful indeterminacy.

The concept can be traced back to The Anxiety of Influence, where it describes one of the stages a poet passes through on the way to achieving true originality. As Bloom puts it in The Daemon Knows, daemonisation refers to 'the poet's breakthrough into a highly individual counter-sublime, thus preferring possession by an inner drive to a debilitating struggle with the already said. A perilous choice, this is endemic in poets whose ambitions transcend all limits.'

Even when they are understood as metaphors and technical terms, religiously inflected words like 'daemon', 'possession', and 'transcendence' are inherently slippery. Their element of mystification is something Bloom makes little effort to avoid. The term 'daemon' is applied loosely and inconsistently throughout. It sometimes refers to an author's influential precursor (Hawthorne is said to be James's daemon; Whitman is Eliot's). Sometimes a daemon manifests itself as the author's own creation (Captain Ahab is Melville's daemon; Huckleberry Finn is Twain's). At other times, the daemon is defined vaguely as a 'poet-in-a-poet' or 'the god within who generates poetic power'.

One of the keys to the book is that Bloom acknowledges Eliot, the least favoured of the twelve writers under consideration, as his own daemon. The show he makes of deploring Eliot's opinions (while admitting a grudging respect for the best of his poetry) is a rather self-conscious demonstration of his theory of influence, an enacting of his agon with Eliot's critical legacy. But it is also the clearest indication of the vulnerability of Bloom's attempt to sustain a comprehensive theory of literature on quasi-psychological and aesthetic grounds, for his personal dislike of Eliot inevitably has its historically determined aspect. As he recalls in The Daemon Knows, Bloom arrived at Yale in the 1950s at a time when Eliot's influence was pervasive. He discovered to his dismay that the famous modernist poet had taught a generation of literary academics to look down their noses at the Romantic poets he most cherished. His subsequent theorising can be viewed in this light as an attempt to appropriate and displace Eliot's ideas about the individual writer's relation to the imposing edifice of literary tradition – one that deliberately inverts Eliot's doctrine of impersonality and reinstates a radically subjective, neo-Romantic poetics.

T.S. EliotMore significantly, Bloom's objection to Eliot is plainly ideological. Though he claims that he no longer feels as antipathetic as he did when he was younger, he remains appalled by the poet's reactionary politics, religious dogmatism, and anti-Semitism, which he characterises at one point as 'genteel', only to describe it later as 'virulent'. At the conclusion of an angry passage that denounces Eliot in these terms, Bloom declares: 'We do notread only as aesthetes – though we should – but as responsible men and women.'

The point is unremarkable, but the admission is significant. We should not read only as aesthetes, even if such a thing were possible, because to do so would mean ignoring the fact that writers address concrete historical realities, not only aesthetic and psychological ones. It is easy enough to agree with Bloom about the inadequacy of literary criticism that takes no account of aesthetics and condemns on narrowly politicised grounds. But as Lionel Trilling once observed, at least part of what we call aesthetic effect is a form of intellectual cogency that derives from a work's social and political relevance.

There would seem to be few subjects as apt to demonstrate this point, few that are as intimately entwined with the major historical and philosophical currents of modernity, than the assertive ideology of American individualism. But on this point The Daemon Knows can only turn in on itself. At one stage, Bloom reveals that there have been times when he has been so gravely ill that he has felt close to death and that he recited Whitman to himself 'as medicine'; later, he refers to his favourite poetry as 'secular Scripture ... Supreme aesthetic experience sustains me through all loss and augmenting presages of the end.'  The inevitable conclusion is encoded in the self-contained and unworldly quality of his theories, and in The Daemon Knows this is tinged with pathos: Bloom's deeply personal relationship with literature expresses not simply an ideal but a felt ultimacy, in the face of which the venerable literary critic is addressing only himself.