Apple's iBookstoreapple.com A book from the Apple iBookstore, as viewed on the iPad.

When it comes to buying and selling books on the iPad, we’re about to witness a strange dance between those who make or sell electronic books and those who read them.

On April 3, when customers pick up their fancy new Apple iPads and want to purchase an e-book, they will have to decide which online bookstore they want to give their money to.

From the start, no one bookstore will come with an advantage: No matter which bookstore application iPad owners choose, they will have to download it first. Even the iBookstore, as Apple writes on its Web site, won’t come preloaded on the device. I Pad owners will be asked to “Download the iBooks app free from the App Store.”

There will also be a swarm of other booksellers to choose from.

As my colleagues Brad Stone and Jenna Wortham reported on Monday: “Amazon.com and Barnes & Noble are working on apps for buying and reading electronic books, even though both companies sell their own e-reading devices and Apple will offer its own iBooks app.” And there are a variety of other free e-book applications, including Stanza and Eucalyptus, which are currently available for the iPhone and offer thousands of free e-books.

The Kindle app for the iPad Amazon’s Kindle app and bookstore will come with the user’s current library of e-books already available.

When it comes to the Apple’s iBookstore, the company proclaims: “Reading is a joy on iPad. Text looks crisp and bright. Pages turn with a flick.”

But the same will be true for all e-books on the iPad, even if they are sold by other vendors.

Some booksellers may try to seduce customers with better pricing or compatibility with their existing e-libraries.

Joe Wikert, general manager and publisher of O’Reilly Media, said in an interview that he believes Amazon will do what it can to maintain its $9.99 price for the most popular e-books. In contrast, Mr. Wikert believes Apple will charge a few dollars more but try to build a richer e-book experience solely around the iPad.

“When has Apple ever tried to compete on pricing?” Mr. Wikert said. Instead, he sees Apple “continuing to build out the device’s capabilities” while adding video and other interactive story elements to its e-books.

Current e-book customers of Amazon and Barnes & Noble will have some incentive to keep buying all of their books from their current seller for ease of use across devices.

For example, Amazon customers will be able to download the Kindle app for the iPad and immediately access all of the e-books they previously purchased for their Kindles or iPhones. Barnes & Noble and other e-book and digital magazine stores also plan to build versions of their software for the iPad and a number of other devices.

Apple, on the other hand, will probably tie its e-books to its devices, just as it has done for the music it sells on iTunes. Such a proprietary strategy didn’t stop Apple from dominating online music sales, so it might work with the iPad, but it’s risky, especially since the current base of e-book customers is so small.

No matter what, with so many choices for consumers on the iPad, e-book sellers will face the challenge of creating new experiences and incentives to lure customers. And that’s going to be good for bookworms.