People who read e-books on tablets are realizing that while a book in print or on a black-and-white Kindle is straightforward and immersive, a tablet offers a menu of distractions.

E-mail lurks tantalizingly close. And if a book starts to drag, giving up on it to stream a movie or scroll through your Twitter feed is only a few taps away.

And some of the millions of consumers who have bought tablets and sampled e-books on apps from Amazon, Apple and Barnes & Noble have come away with a conclusion: it's harder than ever to sit down and focus on reading.

"It's like trying to cook when there are little children around," said David Myers, 53, a systems administrator in Atlanta, who got a Kindle Fire. "A child might do something silly and you've got to stop cooking and fix the problem and then return to cooking."

For book publishers, who have already seen many consumers convert to e-readers, the rise of tablets poses a potential danger: that book buyers may switch to tablets and then find they aren't very amenable to reading.

Maja Thomas, the senior vice president for Hachette Digital, doesn't think that will happen.

"Someone who doesn't have a habit of reading, and buys a tablet, is going to be offered all these opportunities for reading," she said, noting tablets tend to come with e-book apps. "We're hoping they will grow the number of people who will read."

E-readers sales surged during the Christmas season, according to the Pew Research Center.

But publishers may be losing their enthusiasm for tablets as e-readers. A recent survey by Forrester Research showed that 31 percent of publishers believed iPads and similar tablets were the ideal e-reading platform; one year ago, 46 percent thought so.

"The tablet is like a temptress," said James McQuivey, the Forrester Research analyst who led the survey. "It's constantly saying, 'You could be on YouTube now.' Or it's sending constant alerts that pop up, saying you just got an e-mail. Reading itself is trying to compete."

Indeed, the basic menu for the Kindle Fire offers links to video, apps, the Web, music, newsstand and books. So too with the multipurpose iPad, which Allison Kutz, 21, a senior at Elon University in North Carolina, bought in 2010. Ms. Kutz said the only time she was able to focus on reading a book was on an airplane because there was no Internet access.

"I've tried to sit down and read it in Starbucks or the apartment, but I end up on Facebook or Googling something," she said, "and then the next thing you know I've been surfing for 25 minutes."

Russ Grandinetti, vice president for Kindle content, said one reason the original Kindle, introduced in 2007 for $399, was not a multipurpose device was just so people could immerse themselves without interruption.

Mr. Grandinetti said the new Kindle Fire, at $199, was meant as a complement to the first Kindle; different devices for people who want different experiences.

Many publishers believe the market for print books and plain e-readers is not going away.

Voracious book buyers were the first people to latch onto e-readers, prizing their convenience, portability and features like text zooming. Now those e-readers are lighter, sleeker and cost less than $100, so the tech-shy who want a device just for reading books have little incentive to upgrade.

But Mr. McQuivey of Forrester said that it was likely that tablets would eventually edge out black-and-white e-readers. He cited the Palm Pilot, point-and-shoot cameras and portable GPS systems as items that have been displaced by multifunction devices.

For Erin Faulk, 29, a legal assistant and voracious reader in Los Angeles, the era of e-readers has had one major effect: she has accumulated many more books that she categorizes as "DNFs" - Did Not Finish. But she is also buying more books, she said.

"Recently, I gravitate to books that make me forget I have a world of entertainment at my fingertips," she said.

"If the book's not good enough to do that, I guess my time is better spent."

The New York Times