(Nasdaq: AMZN) has one thing over Voldemort. It has just slain Harry Potter.

The leading online retailer announced that the third generation of its Kindle e-book reader has now become Amazon's best-selling product of all time. It tops Scholastic's (Nasdaq: SCHL) Harry Potter and the Deathly Hallows release during the summer of 2007.

Amazon still isn't up to giving us an actual number. It had no problem letting investors know that it moved 2.5 million copies of the final book in J.K. Rowling's series during its debut quarter three years ago. One can also assume that Amazon has probably sold plenty more copies since its debut.

In other words, we're not necessarily any smarter than we were two weeks ago when an official post in Amazon's Kindle forum revealed that it had sold "millions" of the latest model.

It's no surprise to see the Kindle selling so well. The first models were priced at $399 three years ago. The Wi-Fi models now sell for roughly a third of that price tag. Amazon sells the 3G models for less than half of the original -- and with a lot more features.

Amazon may want to thank Barnes & Noble (NYSE: BKS), Sony (NYSE: SNE), and Borders (NYSE: BGP) for igniting a price war earlier this year. Sure, the steep markdowns have zapped margins, but it has helped set the e-reader market apart from Apple's (Nasdaq: AAPL) iPad and the rest of the tablet market.

As CEO Jeff Bezos points out during yesterday's back-patting press release, many new Kindle buyers already own tablets. Consumers obviously appreciate the multimedia and colorful goodness of touchscreen tablets, but there's still an entry-level niche there for dedicated e-book readers that aren't sucking away at limited battery lives.

Now that Amazon has nothing to be ashamed of when it comes to Kindle sales, perhaps we'll get an actual figure of units sold when it reports its holiday quarter report next month.

If you believe that, I have "millions" of reasons why Amazon will not.

Why do you think Amazon has refrained from divulging hard numbers on actual Kindle and Kindle book sales? Share your thoughts in the comment box below.

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Longtime Fool contributor Rick Munarriz owns a Kindle and an iPad, but he uses his iPad a lot more. He does not own shares in any of the companies in this story. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.