Who knows when the first person decided to put something over their head to keep it warm, but knitters know that hats are some of the most fun and easy things to knit.
When they're worked in the round there is little in the way of shaping, except when you get to the crown.
Most hats are worked from the bottom up, with stitches cast-on and worked in a snug stitch pattern such as ribbing, or in stockinette for a rolled bring hat, using a smaller size needle than is used for the head portion of the hat.
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