The pattern calls for worsted weight yarn. I am using sock yarn doubled on 4.5mm needles. The sock is knit sideways. You cast on enough sts for the leg and foot, knit in garter st, divide sts for an afterthought heel, continue knitting the leg, knit the foot, knit the heel, knit the ribbing and last but not least knit the toe, fold in half, seam and you have a finished sock! I was able to finish one sock after a full day of knitting. Pretty good for a sock!