It was almost a complete surprise, barring some leaked early promotional material yesterday. Today, Barnes & Noble has officially announced the Nook Simple Touch with GlowLight, for all the insomniacs to read at night, in bed, without disturbing loved ones. (As B&N noted in a survey it recently conducted, more than 50 percent said they would read more if it didn't affect their partner's sleep.)

The Nook Simple Touch with GlowLight (official name) is nearly identical to the earlier model — same 6-inch E Ink Pearl touchscreen display, same internals, same size and chassis — but is actually hair lighter, at 6.95 ounces vs. 7.48 ounces. And, of course, the GlowLight. Barnes & Noble calls it a patent pending technology that consists of scattering LEDs up top that work with an anti-glare screen protector to uniformly spread light across the screen. There might be some other tricks at play to make it uniform, specifically along the sides and bottom, but they wouldn't tell us anything more. Alas, we only had limited time with the device and weren't allowed to break it apart and explore further.

In practice, the GlowLight works really well. You can see the increased intensity near the top of the screen, but it hits a consistency before any text. Holding the physical 'n' button below the screen for two seconds will turn GlowLight on or off, but you can also adjust the brightness settings via the main menu (accessible via a quick press of the 'n' key) or by pushing the lightbulb icon at the top of the screen (which in practice we could only get to work once or twice). The glow never reached too far beyond the screen itself, and even at lower settings made text legible in dark environments. In daylight and other bright areas, you could see just a hint of the GlowLight when activated, but it didn't affect our reading.

As for battery, Barnes & Noble is still quoting two months without the GlowLight on — same as the current Simple Touch, a number based on 30 minutes of reading each day. With the GlowLight on that whole time (brightness level not clarified), that number drops in half — one month of charge, reading 30 minutes each day in the dark. Which, of course, should still be plenty (barring any extended trips into secluded, cavernous areas).

The Nook Simple Touch with GlowLight will go on sale "in early May" — before Mother's Day on the 13th — for $139, with preorders beginning today. Jamie Iannone, B&N's President of Digital Devices, told us the Simple Touch would remain on sale for $99 and that this would be a "complementary" device. He showed us a new display case for "hero stores" that would place the new Simple Touch with GlowLight in a darker inset to block out flourescent light. The company is currently working on a smaller solution for the "broad chain to have in stores."

Compare this: Nook Simple Touch with GlowLight vs. Simple Touch vs. Kindle family