Digression has a bad rap. "Don't digress," people are always saying, "get to the point," and, of course, the point of the essay is getting to the point, isn't it? But conversation has a way of digressing, or turning aside, and essays are really an elaborate one-sided conversation, or so it seems to me. If you've ever said "now, what was I talking about?" in the middle of a conversation, then you've been practicing the art of digression. The "art" part of digression, however, knows when to return to the subject at hand.

If the essay is a one-sided conversation, then it's likely to veer away from its main point, wander off, so to speak, into speculative territory. In following a spontaneous train of thought, the writer is open to associational deviations; in short, the writer incorporates new strands into the text, and these provide new ways of looking at old material.

And, if reading an essay is also a one-sided conversation, and there's room for readerly digression as well. Far more than when we read poetry or fiction, where the author creates a context for us, in nonfiction we read with a kind of alternative reality in mind—our own. We move rapidly from the text to our own experience and back again, testing what is said against what we know, what is recounted against what we have experienced, what someone else thinks against what we think about the same subject. The reading process is far more interactive, as though you are engaging in a discussion. This, I suspect, is because a major element in reading nonfiction is the assumption of the author's presence as a distinct character. Thus, in a sense, we read to digress—to argue and compare and extemporize—certainly as much as we read to "get there."

This dual nature of the "reading" is built into the genre, and writers of nonfiction need to understand how it works in order to take advantage of it. To digress: to stray from the subject, to turn aside, to move away from. This concept is important, and it's not quite the same thing as changing the subject, or moving toward something else. This is a natural outflow of association, an aside that grows directly out of the material and builds until it has a life of its own, a getting just a bit lost on the way out in order to find new things on the way back.

As writers, we can learn to court digression by learning to trust our own instincts. If, while you're writing, something creeps in unnoticed or else pops instantly into your mind, don't put it aside in favor of where you already sense you are going. No, follow it up by giving it its head. There's time, later, to decide that it was irrelevant. That's for revision, with its long, slow, painstaking taking of stock. In the moment, however, let your conversation get away from you; let a new story take over; follow a mental argument to where it begins to eddy in the current of its confusion. Something may happen along the way, something to alert you to its relevance. And then trust yourself to find the connective tissue—to make your new direction intersect with your old one—because, trust me, the brain has a genius all its own—it struggles to make sense of whatever is put in front of it. So how could you doubt that your brain will find ways to connect what you're thinking about now with what you were thinking about just a few minutes ago? Maybe things have an emotional connection that defies logic. So don't be too quick to scrap what occurs to you. Maybe you want more, not less—a weft across the warp of your initial premise.