Please Note: The following assumes that the reader is familiar with the rudiments of knitting and purling, methods of cast-on, picking up stitches, directional decreases (knit 2 together, purl 2 together, and ssk), grafting (Kitchener stitch), and working in the round over double-pointed needles. If not, please find appended a list of recommended reference works that more than adequately explain these techniques.

Sock Architecture

Conventional handknit socks are made up of five sections: the Leg, the Heel, the Gusset, the Foot, and the Toe. This is by no means the definitive and all-encompassing guide to knitted socks; various sorts of heels (namely the Afterthought Heel, as popularized by Elizabeth Zimmerman) require no gusset, and tube socks have no heel shaping to speak of. Knitted stockings or knee socks require calf shaping, and it is possible to knit socks back and forth in rows and seam them together up the back. However, these alternative methods of sock construction are outside the scope of this writeup. For now. :-)

Materials

You will need a set of five double-pointed knitting needles in the appropriate size for achieving your desired gauge. More about that momentarily. Double-pointeds come in sets of four or of five, the former tending to be used more widely by American knitters for reasons unknown. To divide your work into four equal sections to be worked on five needles makes infinitely more sense than does dividing into thirds. Besides, it looks more impressive. A crochet hook is useful for picking up stitches for the gusset, or for emergency repairs if you happen to drop a stitch and it runs back several rounds. A tapestry needle or wool needle is necessary for weaving in ends.

You will also need some sort of sock yarn. Please, please, please use a wool or a wool blend; acrylic knitting yarns make perfectly awful and unbearably uncomfortable socks (think hot and sweaty feet), and socks knit from cotton are slippery and tend to bunch up around ankles and the backs of heels. One of my favourite sock knitting wools is 75% wool and 25% nylon; it is machine washable and durable enough that it stands up to hard wear. If you have a wool allergy, bite your tongue and knit socks for your friends.

The ballband on your sock wool will give you an idea of the appropriate needle size to use; however, to paraphrase the immortal Elizabeth Zimmerman, this is only a suggestion. Use it as a starting point, do not blindly accept it as a certainty.

Gauge

The bane of most knitters, myself included. Don't overlook it, though; having an appropriate number of stitches to the inch is imperative for achieving correct fit. Row gauge is somewhat less important when knitting socks; measure inches or centimetres for length instead of rows. Before starting, knit a swatch at least two inches (five centimetres) square, block it, and measure with a ruler the number of stitches per inch. Make a note of this number; it will be important later on.

Measurements

A tape measure is absolutely necessary here. If you don't have one, buy, borrow, or steal one before moving on. Have your victim stand on the tape measure laid flat on the floor. Measure from the back of the heel to the tip of the toe, rounding to the nearest quarter-inch (or to the nearest half-centimetre). Then measure the circumference of the largest part of the foot, around the ball. Now you're ready to cast on.

Doing the Math

I lied. You're not quite ready to start. First off, remember the number of stitches per inch from the swatch that you carefully measured and made note of? And remember the circumference measurement? Multiply the former by the latter, and round to the nearest whole number, fudging slightly if necessary to achieve a multiple of two or four for ribbing. Now you're off.

The Leg

Cast on this number of stitches using the long-tail cast-on or an equally elastic method, divide evenly (or close to evenly) over four needles, join, mark the beginning of the round, and work in the round in some sort of edging pattern to prevent curling. Ribbing works well here; that is, (knit 1, purl 1) around or (knit 2, purl 2) around. This requires a multiple of two or four stitches, respectively. Carry out your chosen edging pattern until the work measures about an inch and a half (not quite four centimetres), or until you've tired of ribbing. Then work in stocking stitch (knit all stitches on all rounds) until the work is as long as you'd like it to be, to the top of the heel; a matter of a couple of inches (around five centimetres) for short socks, six or eight inches (fifteen to twenty centimetres) for longer socks.

The Heel

On the next round, knit half of all the stitches onto a single needle. From here you will work back and forth in rows; leave the other half of the stitches for the instep. Turn the work, slip the first stitch, and purl across. On the next (right side) row, (slip 1, knit 1) across. Repeat the last two rows until the flap is approximately square, ending on a wrong-side row. A useful guideline for heel flap length is to work as many rows as there are stitches; this will result in a (nearly) square flap and there is no measurement required.

Now comes the fun part. As feet tend to be at right angles to legs, in order to fit properly a sock must also have a right angle in it; this is called turning the heel and is accomplished with short rows and accompanying decreases. For a typical round heel, knit across half the stitches from the heel flap. Knit one additional stitch, ssk, knit 1, and turn the work. On the next (wrong side) row, slip 1, purl 4, purl 2 together, purl 1, turn. On the following row, work to within one stitch of the turning point from the previous row, ssk, knit 1, turn; slip one, purl to within one stitch of the turning point from the previous row, purl 2 together, purl 1, turn. (In text this last seems to make little sense, but when knitting it becomes obvious; turn one heel and it will become second nature.) Repeat these last two rows until all the stitches from the heel flap have been worked, ending with the right side facing; about a third of the total number of stitches have been decreased out of existence, and you're left with a tidy rounded heel. Congratulations.

The Gusset

Sitting back and admiring your work thus far, you've probably noticed a chain of stitches running up each side edge of the heel flap. These stitches are to be picked up and worked into the foot gusset. Here's where the crochet hook becomes useful; pick up and knit one stitch in each V on the side of the heel. (A small hole almost invariably appears at this point, where the instep joins the heel flap; to avoid this, pick up an additional stitch in the corner and knit into the back of it, thus twisting the stitch. The hole will disappear as if by magic, and all your sock-knitting friends will be astounded by your scintillating brilliance and unparalleled cleverness.) With an empty double-pointed needle, knit across the stitches from the instep (remember them?). Then pick up the same number of stitches down the other side of the heel flap, and on the same needle knit across half the stitches left over from the heel itself. Rearrange the stitches over four needles such that the instep is divided in half on two needles, each side of the foot is on a separate needle, and the beginning of the round is at the back of the heel. Count the total number of stitches; there will be more than the number of stitches you cast on, and that's fine.

Gusset decreases are what make the sock foot-shaped. To work them, you decrease one stitch on each side of the instep every alternate round, working even (that is, without decreases) over the rounds in between, until you've decreased to the original number of stitches and can work even for the length of the foot.

Back to our hypothetical sock. Knit one round even, without increases or decreases. On the following round, knit to the last three stitches on the first needle, knit 2 together, knit 1. Knit across the instep stitches. On the fourth needle, knit 1, ssk, knit to the end of the needle. Repeat these two rounds until all of the extra stitches are gone, and you're left with the original number of stitches.

The Foot

Knit every round until the foot of the sock, from the back of the heel to the end of the work, measures about an inch and a half (slightly under four centimetres) less than the total desired length. Simple enough.

The Toe

The toe shaping described here (the Wedge Toe) is one of the most common toe shapings; it is relatively easy to work, and requires no counting of stitches or rows. (Which is why I prefer it, because I am lazy.) Nevertheless. To work the Wedge Toe, knit to the last three stitches on the first needle, knit 2 together, knit 1; on the second needle, knit 1, ssk, knit to end; on the third needle, knit to the last three stitches, knit 2 together, knit 1; on the last needle, knit 1, ssk, knit to end. Work one round even. Repeat these two rounds until approximately two-thirds of the stitches are gone. Divide the remaining stitches onto two needles, one for the instep stitches and one for the sole stitches. Break the wool, leaving a tail of about fifteen inches; graft (weave) the stitches from top and bottom together with the Kitchener stitch.

An odd-looking but unexpectedly roomy and comfortable toe can be made by working as for the Wedge Toe, but continuing the decreasing until there are about six or eight stitches remaining in total, then breaking the wool and running the end through the remaining stitches. Useful if you can't be bothered to sit down and learn how to work the Kitchener stitch, or if you're knitting socks for a diabetic; this method makes a toe that is wide enough that it doesn't interfere with circulation to the toes.

Fasten off and weave in any loose ends.

Then make another sock to match the first.

"Dance modest but triumphant jig." –Elizabeth Zimmerman

Knitting References I've found the following books and magazines to be exceptionally helpful for explaining various esoteric knitting techniques (including sock-knitting methods), not to mention inspirational in photography and prose. Again, this is by no means an exhaustive nor an extensive list, but it's a good place to start.

Knitting Without Tears by Elizabeth Zimmerman Knitting Around by Elizabeth Zimmerman Knitter's Almanac by Elizabeth Zimmerman Folk Socks by Nancy Bush Folk Knitting in Estonia by Nancy Bush How To Knit by Debbie Bliss Socks Socks Socks by Elaine Rowley and Alexis Xenakis "Interweave Knits" magazine, published quarterly by Interweave Press