This Fool TV video looks at the worldwide shift from analog to digital, a revolution similar to what we've seen with music (as the MP3 has displaced CDs). It's now happening in the publishing business.

Amazon (Nasdaq: AMZN) recently announced that its e-books have outsold hardcopy books. It's sold 143 e-books for every 100 hardcopy books sold. And this happened quickly; Amazon has only been selling e-books for 33 months.

It's done so in the face of concerns over Apple's (Nasdaq: AAPL) iPad hurting the Kindle -- originally, the iPad was seen as a huge threat to Amazon and the Kindle. Hartzell views it differently -- he says it doesn't really matter who wins the device battle. The price of devices will continue to decline as the features offered increase.

Apple has legitimized the e-book market, which will now grow even faster. The real value is in who is going to be selling the bulk of those electronic books -- and Amazon seems to be the clear leader.

Watch the video here:

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