What's the most difficult book you've ever read? For me, at least within recent memory, there's no question—the book that was hardest for me to slog through, the book that I would have put down if I didn't have to read it for work, was E.L. James's Fifty Shades of Grey.

Fifty Shades of Grey is not the sort of book that most people think of when they think of difficult books. Instead, when thinking about books that are challenging, or hard to read, most folks' thoughts turn to imposing modernist book stops like Finnegans Wake (which I haven't read), or imposing philosophical tomes like Kant's Critique of Practical Reason (which I did read, long ago.)

When Juliet Lapidos argued at The Atlantic that you have a moral and intellectual duty to finish a novel once you start it, the books she discussed were by Charles Dickens, Henry James, Ian McEwan—serious novels with some critical standing behind them. Those examples gave weight to her thesis that,"It may be disagreeable to slog through a novel that you stopped liking after 50 pages, but it’s a sign of strength." It makes sense to think of James as push-ups for the brain and soul, or to see McEwan as a fortifying vegetable of prose. If Lapidos had made her case using examples like E.L. James or John Grisham or the Left Behind series, her finger-wagging would have lost much of its oomph.

"Difficult," when applied to literature, generally refers to works that are hard to read, hard to get through, hard to finish. And for me, that describes Left Behind far more than it describes Atonement—the second of which I read twice in quick succession and would read again happily, while the first made me hate life and hope to be transported mid-sentence to another, better realm, somewhere in the sky, beyond this world of sin and hardship and pulp Christian kitsch. There are certainly some highbrow books with sesquipedalian sentences that I've had trouble getting through—Melville's interminable, rambling collection of anecdotes-to-nowhere about the Galapagos Islands, for example. But is my desire to stomp upon "The Encantadas" until it can trouble me no more really categorically different than my desire to hurl John Grisham (or at least his books) from a height?  

In the first case, I know, the fault is supposed to be in me, that I have failed to look deeply enough into the work of a master. In the second case, most people would say the fault is in John Grisham's shockingly vapid prose and brain-dead plots. But in both cases, the experience is one of repulsion, boredom, alienation. Melville and Grisham: They're both difficult for me to read.

So why should readers be open to labeling Fifty Shades as difficult (at least for some), rather than as just bad? There are a couple of reasons. First, I think it's more true to the experience of reading to see "difficult" as wrapped up in evaluation of "bad," rather than as separate. Most people are willing to admit, even if grudgingly, that aesthetic quality is to some degree subjective. You may (as I do) find Art Spiegelman's Maus a tedious, pompous slog, but that's a judgment about which reasonable people may differ (even if, of course, all right-thinking people agree with me.) But "difficulty" seems to hold out the possibility of more objective standards—to assure us that these books, over here, by Joyce and Faulkner, are 1000 pounds of pure prose, while these books over there, by Stephenie Meyer or Tom Clancy, are sniveling 90-pound weaklings of meretriciousness. It's as though "good" may be relative, but "tough" is always and everywhere the same.

Again, the problem with this is that it isn't true: "Difficulty," like "good" or "bad," is subjective. Some folks (okay, many folks) may be put off by Henry James's endless sentences and deliberately opaque social vacillation, but others may find it engrossing. Some people may love to flip their way through Jack London's manly adventures; others may find a novel's worth of cruelty to animals so upsetting as to be unreadable. Some people may love the sweep and romance of Gone With the Wind; for others, the unrelenting, vicious racism may be off-putting. For that matter, most reader surveys indicate that men, as a group, don't read fiction of any sort.  Does that mean that men are serious-minded readers of non-fiction? Or does it mean that romance novels and mystery novels, those quintessential guilty pleasures, are, at least for some, difficult?

"I'll be grateful," Megan Stephan writes at Public Books, "when the back-and-forth chatter about whether our reading should make us feel guilty fades to a silence that allows me to hear the sound of pages turning." That's a widely held sentiment.  In our poptimist era, "guilty pleasures" have been so thoroughly recuperated that it sometimes feels like the only thing about which you're allowed to feel guilty is feeling guilty. But despite this broad validation of reading enjoyment, or perhaps because of it, displeasure continues to be viewed with unease.

"Difficulty" is one way to dismiss that unease—to say, well, if you don't like this important novel, it's because you aren't willing to do the hard work required to understand it. But recognizing that difficulty is various and subjective doesn't mean I should try harder to like Fifty Shades. Rather, it's a way to point out that opacity and frustration aren't necessarily errors or failures on the part of the reader. The experience of reading is often the sound of no pages turning—an absence as varied, as complicated, and as important as pleasure.