If you're serious enough to actually contemplate — or even dream about — the purchase of a high-definition television, you don't need someone like me to tell you how good it is. You've got the bug already. You want a new toy. Then again, you might fall into my category: You really crave that shiny new HDTV, but your discretionary income is tied up in children futures. So you just hang around your local electronics emporium and dream.

Well, no matter who you are, and even if your only TV is a black-and-white museum piece, television's digital revolution is edging your way. HDTV is real, it's here, it's viewable in every American home, and you no longer face the choice between buying a high-definition television and owning furniture.

My purpose in this space is not to tell you what brand, size, shape, or style of TV set to buy. There are simply too many choices out there. But that's the problem. Negotiating the retail world of HDTV is still, to put it charitably, chaotic. So let's begin with a techno review. And, yes, there will be a test — the minute you start shopping.

What is HDTV?
High definition television is a revolution, a wholesale conversion of America's TV system to a better way of sending and receiving pictures and sound. An HDTV picture is big and wide and sharp, shaped more like a movie theater screen than the squarish pictures we're all used to on television. It comes with CD-quality, five-channel surround sound.

Oh, I see. This is just some conspiracy to make me buy a big, wide, expensive TV, right?
Yup, and it's all brought to you by the aliens that landed at Roswell. Truth is, HDTV is revolutionary. The U.S. broadcasting system, proceeding under a Congressional mandate, is in the midst of a conversion that is affecting TV networks, cable companies, local stations, manufacturers, and consumers alike. But it's not just some excuse to make you pry open your wallet. HDTV is the ultimate form of digital television, which treats TV much like your computer handles images and sound.

And exactly why is that better?
Very simply put, TV comes to you today — whether through the air, via satellite, or down the wires of a cable system — in radio waves. That's the essence of the "analog" TV that has been the U.S. standard longer than most of us have been alive. As you well know, if there's a storm or some other interference, you might get a snowy picture, ghost images, or crackles in the audio. Not in the new world. Digital sounds and pictures are transmitted and received in the zeros and ones of a computer file. It's on or off; you get a perfect picture or no picture, pristine sound or no sound.

I know. I've got a DVD player and digital cable.
Actually, while that DVD player may be a digital device, your current TV very likely isn't. The DVD player has to convert the signal back into analog for you to view it. Compared to a VHS tape, digital cable or a DVD looks great. But compare it to HDTV, and you ain't seen nothing yet.

You see, it's all about pixels. A picture comes to your TV set as horizontal lines, which are divided up into tiny squares called pixels (picture elements). Each pixel is actually made up of even tinier dots of red, green, and blue. Think of a pixel as a tile, very much like the mosaic tile pictures you may have made in camp or in art class — when you weren't busy eating paste. Well, if you're trying to make a picture out of large tiles, it's going to seem rough and jagged, not very detailed. But the smaller the tiles (pixels), the more of them you'll be able to fit in the frame, and the richer the detail and shape of your picture.

Today's analog TV sets are generally capable, in practice, of displaying about 640 pixels horizontally and 480 pixels vertically. If you're watching a VHS tape or analog cable, you are most likely seeing fewer pixels than that. With a DVD, you're pushing the limit of most TV sets. (For comparison purposes, that 640 x 480 pixel count is about the resolution of a lousy, antiquated computer monitor. Most PC screens today display at least 600 pixels by 800 pixels, and many go to 768 x 1,024.) HDTV quality, depending on the brand and type of set you pick, starts at 720 pixels by 1,280 pixels and goes all the way up to 1,080 x 1,920. That's almost 10 times the number of pixels of today's average TV viewing experience. That means sharpness, yes, but also lifelike, saturated color. There's a whole lot of tiny little mosaic tiles. It's an astounding artistic palette for talented filmmakers. A mountain vista, a rainforest, or a cheetah's fur will look real enough to touch. In HDTV, you'll be able to count the teeth on Jerry Springer's guests like never before.

What's the big deal about wide screens?
If you ask a professional photographer, she'll tell you that square screens (today's TV is pretty darn close to square) are static. It's difficult to compose dramatically, to lead the viewer's eye around the screen. Now imagine you're at the movies. That wide frame makes for more dynamic pictures that don't just exist in the center of the frame. That, in a nutshell, is the widescreen TV difference. You get a more dramatic view of everything from a touchdown pass to the homeowners' despair when they really hate the makeover results on Trading Spaces .

OK, so suppose I don't want a big, honking TV in my den. What's in this digital technology for me?
Plenty, actually. Digital TV doesn't have to be HDTV. There are lower resolution digital sets, which look terrific in smaller screen sizes. At its worst, digital TV looks at least as good — and probably better than — the picture you get from your DVD player.

And that brings us to an important digital wrinkle. An HDTV signal — whether it's coming through the air, down a cable, or from a satellite dish — is a ton of digital information. In nerd terms, the "bandwidth" required for one HDTV program is as much as four of today's "standard definition" signals transmitted digitally. Well, during daylight hours, many local stations may not broadcast in HDTV. Instead, they have the capacity to send out four standard-definition video streams ("multi-casting," in geekspeak). That means the same station might send out a cooking show, a kids' show, a stock market ticker, and last night's newscast — all at the same time. Some broadcasters are also contemplating using one of those multi-cast signals to send Internet data.

So I'm gonna need to buy new DVD player? And what about my VCR?
Both will still work with an HDTV, but you won't see any improvement over the pictures you're watching on your regular TV. But there is a new generation of DVD players out (you might even have one and not know it) called progressive-scan players. They play the same disks you've got now, but when hooked up to an HDTV, they look about twice as sharp as standard DVD players. If you don't have a DVD player already, a progressive scan model doesn't cost a fortune (some are around $150 these days), and you'll appreciate the difference on any digital TV. HDTV VCRs are, as a realistic possibility, still a ways from being practical or affordable.

OK, let's get real, TV Boy. Maybe an HDTV won't cost as much as a car, but I'm still going to be eating fish sticks and Tater Tots for a couple of years before I pay for it, aren't I?
I can answer that question in two words: Atkins diet. But seriously? We're pretty spoiled these days. Television sets cost less than ever. A 25-inch TV — from a manufacturer you've actually heard of — can be bought, without breaking a retail sweat, for less than $250. Decent DVD players and good VCRs can be under $100. An HDTV set still commands a premium. The first sets that hit the market were often well above $10,000. Some still are. But prices have tumbled. The low-price end of HDTV sets is now under $2,000, for a complete package. If you're contemplating the purchase of a big screen, rear-projection set (and a lot of people have them these days), I think you'd be nuts not to go with a set that's at least capable of displaying HDTV. Dirt cheap, no. But when you're talking about big-screen sets, venturing into the future might only cost you a few hundred extra dollars. That's certainly in range for real-world purchases. Maybe when you do the kitchen remodel, you can settle for less than the Sub Zero refrigerator. All you'd be putting in it is those fish sticks and Tater Tots, anyway, right?

What happens if I just stick with Old Sparky, my current TV?
For a while, nothing. You and your family can just gather around the radio or crank up the old Victrola for entertainment, too. We're at least a four years away from a complete switch to digital. The governmentally inspired goal (which allows for extensions) is 2006. But if you're still skeptical, just go look. Go to a high-quality electronics store and watch HDTV on a good set. Then try to go back. You'll be spoiled, too.

Once I buy this new TV, is there anything actually being broadcast in high definition?
Programming is taking off. If you think I'm lying, check out the weekly HDTV program listing on the HDTV Galaxy site ( http://www.hdtvgalaxy.com/broad.html ). There are offerings on Discovery HD Theater (hey, I had to get in a plug here somewhere), accompanied by other big-time cable and broadcast names you know. There are more movies, sports, and series coming on in HD all the time.

So, what do I do, just go in a store and say "gimme one"?
You need to do a little homework. HDTV is, indeed, a revolution. But electronics revolutions take time. Remember: This is a top-to-bottom conversion. Imagine what it would be like if we had four years to convert every car in America to run on hydrogen fuel. Change takes time. Many, but not all, retailers are beginning to get better about selling and explaining HDTVs.