Innovation manifests itself in myriad ways: groundbreaking, revolutionary bursts we'd never before imagined possible, or in more nuanced but no less brilliant refinements of existing technology. And while this year's list contains plenty of instances of the former, in compiling it we've noticed one thing: 2009 is the year of stealth innovation.

Here’s what I love about the elegantly functional stethoscope that is the recipient of our 2009 Innovation of the Year award: It looks exactly like a stethoscope. Jointed arms connect earpieces to a black rubber tube that leads to a circular amplifier—you’ve seen one every time you’ve visited your doctor since you were born. It takes an observant eye to notice that on this one, there’s a tiny screen on the back of that amplifier, and telltale + and – signs and a small power button that signify electronics in action. The creators of this high-tech medical tool have taken an instrument that’s been central to medical diagnostics for 190 years and supercharged it, adding sophisticated hardware and software that record, transmit, and analyze vital data, dramatically improving doctors’ ability to detect truly dangerous heart murmurs while eliminating the need for thousands of pricey echocardiograms a year. But from a design standpoint, I’m pleased to see that the stethoscope’s reinventors have decided that it ain’t broke, so don’t fix it. Thus they’ve come up with a device that still carries all the Norman Rockwell–style reassurance of its predecessors.

As you click through our annual Best of What’s New Award coverage online, you’ll see all sorts of gizmos and breakthroughs whose “wow!” attributes, the reasons we decided they were one of the top 100 innovations of the year, are immediately apparent: a 54-inch-screen plasma TV that’s an inch thick and completely unencumbered by cables; a privately developed and launched rocket that successfully delivered payload to orbit; an electromagnetic helmet that could cure depression. But a higher-than-usual proportion of winners this year seem to follow the stethoscope model of reinventing within an extremely familiar form: a DSLR camera that shoots studio-quality movies; glass so strong you might one day be able to build a skyscraper out of it; wallpaper that can protect a building against a bomb blast.

These winners provide proof that breakthrough technology doesn’t have to be flashy to be effective. Nothing illustrates that better than our Innovation of the Year, a device you may have already seen—but didn’t notice—hanging around your doctor’s neck.

Click here to explore the list