Just months ago, the e-book reader market seemed like a footrace between Amazon.com (NASDAQ:AMZN) and Sony (NYSE:SNE). Now it's quickly becoming a crowded marathon.

California-based Spring Design introduced the world to Alex yesterday. The dual-screen reader is billed as the first e-book device based on Google's (NASDAQ:GOOG) Android mobile OS, allowing full Internet browsing over Wi-Fi or mobile networks.

The design resembles the snapshots leaked last week of Barnes & Noble's (NYSE:BKS) upcoming reader, with a smaller LED color touchscreen on the bottom to enhance the E-ink text reader on top. No price has been revealed, but Spring Design expects Alex to be out in the wild by the end of the year. It's currently in talks with content partners, and the device's mobile networking aspect may pave the way for a subsidized reader through wireless carriers.

Don't forget Barnes & Noble, either. It officially introduces its e-book device this morning, but The Wall Street Journal has already revealed that the massive bookstore chain's reader will be called Nook, priced aggressively at $259.

The price is bold, because it matches Amazon's Kindle. I figured the Nook's multitouch color screen would drive its price into the $300 to $400 range. At $259 -- and promoted in the world's largest bricks-and-mortar bookstore chain as the holidays approach -- you have to like the Nook's chances.

If claustrophobia is starting to kick in, consider that Apple (NASDAQ:AAPL) hasn't made an entrance to the market, beyond App Store readers for the petite iPhone and iPod touch. The real game-changer would be a tablet Mac. But now, one has to wonder whether Apple may price itself out of this market, given Alex's surfing skills and the Nook's cutthroat price point.

With more and more big companies sporting even bigger plans to legitimize the digital book revolution, this will be a huge holiday season for e-book readers.

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Longtime Fool contributor Rick Munarriz has been shopping online for about as long as Amazon.com has been in business. He owns a Kindle. 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.