Opened a parcel of hand-dyed yarn and found a beautiful twisted bundle instead of a ready-to-use ball? You're not alone. A skein isn't an inconvenience or an oversight. It's a deliberate part of how quality, hand-dyed yarn is produced and sold. Here's what a skein is, how it differs from a ball, cake and hank, why dyers use this format and how to wind a skein of yarn into something you can knit or crochet from.