Ahead of the publication of Margaret Atwood's new novel Maddaddam later this month, I found myself re-reading a review by John Updike of The Blind Assassin, her multi-award winning novel from more than a decade ago.

This led me on to some of the pieces alongside his review, gathered in a breezeblock of a book called Due Criticism. Updike opined easily and profoundly on a wide range of subjects - art, authors, life itself. As he wrote of attending his high school reunions, not only did he never miss one, but rarely did he come away without an idea for a short story, although he did not - presumably felt he could not - always write them.

The heft of that work of critical journalism would have been testimony enough for most people of a life profitably spent. For Updike, though, while his criticism was important, it was not his main occupation. It exercised one particular literary muscle, without which his fiction would have been less brilliant, yet it never usurped his raison d'etre. Reviewing merely filled the gaps between the hours of writing fiction and paid the alimony and other bills while advances were in the offing, or royalties slow to appear.

A glance at the oeuvre of a writer like Updike - or indeed Atwood - is humbling. Even more so is Joyce Carol Oates, probably the most famous modern example of a writer whose tap is always turned full-on. She has, sadly, suffered for this. Her ceaseless flow of exceedingly well-written books first raised eyebrows, then suspicion. How could someone write this much and still be good? Whoever coined the phrase "typing not writing" must have wished they'd been paid every time it was trotted out thereafter.

But glance at the sort of novelists who publish so regularly that in medieval times they would have been harnessed to pendulums so we could tell the time by them, and it becomes plain that being prolific has no bearing on quality. Unless one argues - and one certainly could - that some of the best writers who ever lived were astonishingly productive.

Perhaps our instinctive mistrust of them is plain jealousy. Those who can think so fast and clearly, who can hold a complicated story in their head better than we can remember a shopping list, are possibly viewed with scepticism because we wish we could emulate them, and know we never could. Or perhaps it goes deeper than that, back to the days of the first factories, when production lines ousted hand-made goods, making inferior products in a fraction of the time, and giving speed a bad name.

Look at Balzac, Simenon, Dickens, Trollope or Sir Walter Scott, however, and the idea that their novels are less well written, executed or conceived than more ponderous counterparts is dismissed. For such writers there is no barrier between thought and page. Shakespeare's publisher said of him that "His mind and hand went together, and what he thought, he uttered with that easiness that we have scarce received from him a blot in his papers."

Meanwhile, Scott's secretaries were left puffing in his wake, as he dictated to them as if he were a steam train (which had only just been invented). At his peak, he spilled out two of his Waverley novels in three weeks, faster than most of us could read them. Then there's Anthony Trollope who in his autobiography describes how, despite his demanding position with the postal service, he set himself a target of writing 10,000 words a week and, by using his daily train commute for this purpose, rarely missed it. That was nothing, though, compared to Erle Stanley Gardner, author of 140 mystery novels, who would dictate 10,000 words a day. He, however, is unlikely to grace the hall of immortality in quite the way as the others mentioned above.

Such is the fury with which some writers compose, one gets the feeling that their novels are mere extensions of themselves, as natural and essential as breathing. Their only problem is that they have more stories to tell than time in which to tell them.