Barnes & Noble, Sony and other eBook vendors may be the manufacturing brawn in the ongoing e-reader war, but the brains directing the challenge against Amazon.com's market-leading Kindle is Adobe.

On Wednesday, the software maker tallied up its alliances and customers in a bid to show that while this holiday season may belong to the Kindle, future ones will not.

Adobe announced that more than 100 publishers, book retailers and libraries are using Adobe's Content Server 4 software to deliver encryptable eBooks via the two formats favored by Adobe: PDF and ePub.

These include 17 eBook reader manufacturers who have licensed the Adobe Reader Mobile Software Development Kit (SDK) to enable their readers to display PDF and ePub-formatted eBooks.

A total of 30 eBook readers rely on Adobe software, including the aforementioned Barnes & Noble and its just-debuted, already-delayed Nook ; Sony and its popular Sony Readers ; and others, according to Nick Bogaty, senior business development manager for digital publishing at Adobe.

Both PDF and ePub are open industry standards, though the optional encryption and DRM provided by Adobe's Content Server and enforced by the Adobe Reader, are not.

Though Adobe may balk at the comparison, its role in the eBook market is similar to Microsoft's in the PC market: a builder of a semi-open ecosystem of partners to whom it sells publishing tools.

In this analogy, Amazon.com is like Apple: successful, but secretive, with a reliance on proprietary formats like the Kindle's native AZW that creates customer hassle and lock-in.

For instance, a Nook user will be able to buy eBooks from stores other than Barnes & Noble, as well as transfer eBooks back and forth to a computer or other eBook reader, such as a Sony Reader, without fear of hiccups.

That is technically possible via the new Kindle DX's support for PDF, but it's more of a hassle, especially since Amazon.com has declined to adopt ePub or, more crucially to Adobe's bottom line, its Content Server software.

"Customers want to decide which devices they read their eBooks on," said Adobe's Bogaty, former executive director of the International Digital Publishing Forum (IDPF). "That's in direct opposition to closed approaches like the Kindle, where you don't have alternatives."


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Amazon.com took exception to Adobe's characterization, while hitting back.

"Our approach is to make sure you can read your Kindle books on any device. We already support iPhone, iPod touch, and the PC, and will have many more in the future, such as Blackberry and Mac," an Amazon.com spokeswoman said via e-mail. "The Kindle format has features like Whispersync that are important to our customers and so far it's working well."

Moreover, "our thoughts on ePub are that ePub isn't open if you wrap DRM around it," she said.

Adobe's other argument is that the Kindle's failure to support ePub could put it at risk of being ignored by publishers eager to Flash videos and other multimedia elements inside their eBooks. eBook readers with colour LCD screens, or netbooks and tablet computers such as Apple's long-rumored device, are starting to emerge.

They can display those new breeds of eBooks, unlike today's Kindle with its slow, monochrome screen.

"There are so many companies coming to market with wares that go beyond E-Ink devices," Bogaty said. "We don't have to be smart enough to know which is going to be the ultimate reading device."

Publishers may be unwilling to bear the cost of republishing their multimedia books for the Kindle. It could be Betamax versus VHS all over again, with Kindle being the closed format that falls behind, said Tim Bajarin, an analyst with Creative Strategies Inc.

"I believe that the Adobe approach is ultimately the one that will have the broadest industry adoption," he said. "They have all of the content guys. They have all the players [on-board.]"