Rest easy: Payback, the published version of Margaret Atwood's 2008 Massey lectures, is neither a treatise on economic principles nor an instant book about the unfolding market crisis. Instead, it is concerned with "debt as a human construct," and how "this construct mirrors and magnifies both voracious human desire and ferocious human fear." Debt, then, as an "imaginative construct" as well – a logical point of entry for a novelist and poet.

"The things that puzzle us as adults begin by puzzling us as children," Atwood notes in the first essay, Ancient Balances. Her own childhood was full of puzzles, ranging from the mystery of payment by the tooth fairy to the behaviours of a hot-tempered, tight-fisted cartoon character named Scrooge McDuck. Early life taboos regarding matters of money and God, she believes, engendered an ongoing inquiry in her into the "peculiar nexus where money, narrative or story, and religious belief intersect, often with explosive force."

As its title suggests, the opening essay meditates on the human sense of fairness and justice. Systems of debt and credit are founded on an innate need for balance in exchanges. Debtor and creditor are "two sides of a single entity." The impulse, which may even be pre-human – monkeys show similar inclinations – is fundamental to the success, or simply the survival, of economies and societies. It may be no less essential, Atwood argues, to ecosystems themselves.

Debt and Sin and The Shadow Side explore the various contracts that emerge from the debtor-creditor relationship. From the Faustian pact with the Devil, dubbed "the first buy-now, pay-later scheme," to debtor's prisons and loan sharks, arrangements have long been made that sorely test the concept of balance. The case of Shylock in Shakespeare's The Merchant of Venice, where the distressed moneylender opts for vindictive revenge – the notorious "pound of flesh" – over sound fiscal sense, is one such instance. So are popular uprisings against egregious taxation.

The middle essay, Debt as Plot, serves as the book's fulcrum, using the second of three visitations with the figure of Ebenezer Scrooge, from Dickens's A Christmas Carol. Debt, a governing leitmotif in Western fiction, came to dominate the concerns of 19th-century novelists. The preoccupation coincided with the ascendancy of capitalism, where "people began substituting something called 'the Market' for God." Money has certainly remained the measure of most things ever since.

After examining the creditor/debtor contracts in fiction by Washington Irving and Edith Wharton, William Thackeray and George Eliot, Atwood returns to Scrooge's Christmas Day salvation. Unlike previous penitents, such as Marlowe's Dr. Faustus, Dickens's old miser isn't obliged to give up his wealth to procure happiness. Quite the opposite: He just has to spend it on turkeys and gifts for the poor, care enough to ensure that God will bless Tiny Tim.

"Scrooge's happy ending," she writes, "is therefore entirely in keeping with the cherished core beliefs of capitalism. His life pattern is worthy of Andrew Carnegie – make a bundle by squeezing and grinding, then go in for philanthropy." Her range of literary references is sweeping, if a little predisposed to following the money, rather than the faith, in many of these works.

Payback, the fifth and final essay, offers Atwood at her most political. "Every debt comes with a date on which payment is due," she warns. By way of evidence, she re-configures A Christmas Carol as a 21st-century parable of planet abuse: our accumulated debt to the earth as yet unpaid, and with time running out.

"Scrooge Nouveau," as she calls her own cross of McDuck and Dickens, is a corporate executive suffering three visits during his long night of "Earth Days," Past, Present and Future. "Spirit! What's happening?" he asks in a typical exchange. "You're witnessing a moment of hyperinflation," the Spirit of Earth Day Future answers.

Who knew talking about debt could be so funny? Where blazing prose riffs or witty turns of phrase don't provide enough humour, the essayist isn't above inserting a straight joke, complete with punchline. Indeed, Payback displays some of the energy of a lively dinner party, one replete with anecdotes and opinions, witticisms and barbs. Talking about debt, it turns out – Atwoodian debt, at least – is also serious adult fun.

Summarizing the trajectories of these essays does scant justice to their richness. By now it is almost redundant to remark on Margaret Atwood's formidably lucid intelligence. The quality is certainly in evidence here, if worn with a lightness that could pass for courtesy to readers and radio listeners alike. Those seeking examples of her career gift for prophesy, meanwhile, need look no further than the timing of her Massey lectures – and this accompanying book – with the breaking news.

Comments about the "ballooning and ruinous and nation-weakening and out-of- control big fat American debt," or questions concerning "the use of debt as a sophisticated investment vehicle," while written in the halcyon days preceding the ongoing financial meltdown, are certainly resonating. Likewise one of the Spirit's digs at the hasty efforts at restitution by Scrooge Nouveau's corporate buddies: "Could it be that they sense an impending global crisis?"

Maybe Payback is more about economic principles, and even the market crisis, than it appears at first glance. As impressive as Atwood's intuitions, or her intellect, or even her humour, is her insistence on tracing responsibilities, and possibilities, back to those human, and thus imaginative, constructions.

"All human technologies," she writes, "are extensions of the human body and the human mind." Or this bold challenge to Economics 101: "In our minds – as reflected in our language – debt is a mental or spiritual non-place." The call here, expressed with great passion and quiet anger, is to reassert human agency over the ultimate creditor-debtor relationship. Moral debt, in effect: the kind that money can't pay off.

"How do I even begin to pay back what I owe?," Scrooge wonders the morning after his own awakening to the Earth's fragile beauty. "Where should I begin?"