Steve Sem-Sandberg's The Chosen Ones may be a brick of a book - but I'm not giving up

Sem-Sandberg's novel is set in a children's clinic in Austria, which became part of the Nazi euthanasia programme

In it for the long haul: memorial for the children of Am Spiegelgrund, Vienna (Alamy)

I am currently 150 pages into Steve Sem-Sandberg's new novel, The Chosen Ones, which is little short of 600 pages. It is set in Am Spiegelgrund, a children's clinic in Austria, which, during Germany's annexation, became part of the Nazi euthanasia programme. It is told, alternately, from the point of view of a child from a poor, dysfunctional family who lives in it, and a nurse who works there. In a letter to readers, the book's editor, Lee Brackstone, says: "I hope you'll find time to commit to this book – and I recognise it is a commitment".

Having begun it, I appreciate Brackstone's words, though they make the novel sound a little like a hardship, which it isn't. But neither is it a story we are distracted or entertained by or one that helps to take the edge off our commute, like those infernal games of Candy Crush. It demands something of us, a facing up to a horror and a level of misery that is both specific and universal.

This is perhaps why James Patterson's initiative called "Bookshots" rankles more than it might otherwise. Patterson is to launch a line of novels that he hopes will get book-shy types reading. He'll do this by making them short, cheap, plot-driven and available in groceries and drug-stores, like the old dime novels, according to a report in The New York Times. They will be written to be read in a single sitting at under 150 pages. "You can race through these – they're like reading movies," he is quoted as saying. "It gives people some alternative ways to read."

To set up in direct competition with video games, films and social media (which is what Patterson is doing) is a feisty move, but my fear is that these "alternative ways of reading" might become their own kind of reading, one which requires a fast, undemanding McBook. And that this might create a hybrid reader whose concentration span stretches beyond 140 characters – but only just.

It is certainly a sign of the times when the publication of a thick book warrants an editor's explanation, but there is a reassuring backlash too this spring and summer, when many doorstop-sized novels will demand concentrated reading from us, including Annie Proulx's Barkskins (717 pages), which is big enough to kill a small scuttling thing beneath its weight. So are CE Morgan's The Sport of Kings (545) and Maggie O'Farrell's This Must be the Place (483). Thank goodness for these, and The Chosen Ones too, they are stories whose demands are equal to their gifts. They might not tell it all in the time it takes to travel to work, but keep to the commitment and you enter an exchange that rewards deeply.

Or if a book is too long for your liking, you could simply give up on it. Men – we were recently told in a survey – are more decisive when it comes to discarding a book. Women tend to bear with it. Whether this correlates to gender conventions is not as interesting as evaluating the value of these two approaches. It also reminds me of an old joke I share with a university friend that still makes us snigger stupidly when we see a copy of AS Byatt's Possession. It relates to a time, shortly after it was published, when we were all apparently reading it. The joke began when this friend spotted my copy yellowing on the bookshelf and smiled slyly when he opened it at the single page I had turned down.

"So you haven't read beyond page 20?" he said, and before I could deny it, he was telling me that he hadn't either, and neither had anyone else he knew. In fact, he said, he had been thinking of having a Possession bonfire, so that we could all bring our sacrifice to the Half-Read Book barbecue, and grill some sausages afterwards.

It is a puerile joke. Lots have read all of Possession and loved it. It won the Booker prize, for Heaven's sake. It is surely my (and my friend's) failing, not Possession's. But there is a legitimate issue here too: can we, men and women, give up guiltlessly on a book? If so, how many pages are fair game? How do we know that the narrative – of a film, book, exhibition – won't turn a corner and everything that has come before will be illuminated and redrawn with meaning?

A fellow critic has a 40-page rule; it is all in the voice, she says, which can be judged in these pages. Film critics shuffle out with casual regularity at the screenings I attend. Tracy Chevalier has spoken of the value of visiting an exhibition and not consuming it whole but homing in on one image, absorbing its singularity. Meanwhile, the half-read book might be waiting patiently to be given another go. Maybe this time, we won't hit the buffers with it. No bonfires necessary.