From Harry's simple red cable sweater from the film climax of Harry Potter and the Philosopher's Stone to the complex patterns of a variety of Aran or fisherman sweaters, cables are a key component of knitting designs. And, like all good knitting skills, no matter how complicated or intricate the pattern, it's achieved by a very simple technique: rearranging the order you work the stitches.

Cables can be wide or narrow, compact or elongated. Typically, they're worked in stockinette stitch on a background of reverse stockinette; this makes the cables stand out even more. Most cables aren't going to be wider than about 10 stitches because the process of cabling pulls the fabric, and moving stitches farther than that will pull rather a lot.

A basic cable is usually four or six stitches wide, and the direction the cable turns depends on whether the stitches are held in the front or the back of the work. Holding the stitches in front of the work will give you a left-leaning cable, while holding the stitches behind the work will make a right leaning cable. This holds true no matter how many stitches are involved.

For me, the easiest way to work cables is to use a cable needle, which is a short, double-ended needle that you use as a temporary holder for the stitches being moved. I like the added sense of security of having a needle in those stitches when moving them. Of course, you don't have to use an extra needle at all; Wendy of WendyKnits has an excellent tutorial for cabling without a cable needle, if you're feeling adventurous.

For simple instructions on how to knit a basic cable, let's look at Margaret Radcliffe's basic instructions from The Knitting Answer Book.

1. Slip half of the stitches onto the cable needle purlwise. Place the cable needle in front of or in back of your knitting. In front it makes a left-slanting cable. In back it makes a right-slanting cable. You don't need to hold onto it: Just let it hang.

2. Knit the other cable stitches from the left needle.

3. Without turning or twisting the cable needle, hold it in your left hand with your left needle and knit the stitches from it, then continue across the row. Work several rows in the knit-and-purl pattern before crossing the cable again. For a two-stitch cable, you may cross it on every right-side row. For wider cables, crossing every fourth, sixth, or eighth row is more attractive.

Cable terminology across patterns isn't entirely consistent. Some patterns will simply write out the directions in the pattern line; others will use an abbreviation within the instructions. When patterns use abbreviations within them, most will provide an explanation of what it means, usually near the beginning of the pattern. It may seem frustrating to have to keep checking this, but you'll find that, as you work more with the pattern, the more you'll remember what the abbreviations mean.

Once you've made one knitted cable, you can do any of them. So give it a try; they're really fun to knit, and they look so darn impressive.