NEW YORK — The lighter, slimmer, cheaper new version of Barnes & Noble’s e-reader has a black-and-white touch screen and aims squarely at the “grandma” demographic — or at least those craving a simpler e-book reader.

The latest Nook’s price tag, $139, is a sign that the book seller also is aiming to compete with Amazon and Borders Group Inc. on e-reader prices.

The focus on simplicity means the new Nook’s battery can last two months, CEO William Lynch said at an event in New York to announce the device. Lynch told the crowd of bloggers, news media and analysts the latest Nook was inspired by feedback from customers — specifically a letter asking why no e-readers were suitable for a grandma.

“The Kindle 3 has 38 buttons. That’s 37 more than the all-new Nook,” said Lynch, taking a jab at Amazon.com’s e-reader, the market’s top seller.

The new Nook, to be available June 10, is Wi-Fi only, has a 6-inch touch screen and can hold up to 1,000 digital books. It has the latest E Ink technology, significantly minimizing flashes that can occur as a user pages through an e-book. Pages seem to melt into each other on the new Nook.

The newest device replaces versions that came before the Nook Color, which still sells for $249. After the all-new Nook’s release, the first-generation Nook will sell for $119, and the Nook 3G will sell for $169 — until supplies run out.

Morningstar analyst Peter Wahlstrom said the newest version keeps Barnes & Noble current, while reserving the company an option to release a more tablet-like device later.

“You don’t have to get into the really crowded tablet space right away,” Wahlstrom said. The simplified reader — which does not allow users access to an app store like the Nook Color does — can appeal to current Nook owners who want a technology upgrade and to “the incremental consumer who is used to touch screens and a more simplified version of technology.”

Barnes & Noble Inc. executives said the new device lets readers look up words, highlight passages, search and adjust font size. It weighs 7.5 ounces, 35 percent less than the first Nook, which launched a year and a half ago. The iPad 2 weighs more than 1.3 pounds, roughly three times as much as the newest Nook.

The newest Kindle is almost as light, at 8.5 ounces, but holds more than three times as many books as the new Nook.

Amazon, meanwhile, dropped the price of its Kindle last month by $25 to $114, though with a catch: The new Kindle with Special Offers includes advertisements on the bottom of its home screen and on screen savers.

Borders and its Kobo partner said Monday that they are taking preorders for a $130 touch-screen e-reader that launches in early June.