I learned how to knit as a child and found it to be calming and fun with a nice sense of accomplishment after I finished even the simplest item. My daughter is learning knitting basics and has made a few small things so far, including a headband.
Creative Kids Complete Photo Guide to Knitting has lots of photos, clear, concise instructions and simple language which is easy for children to follow. Younger children may need some adult assistance, but my daughter is a young teen and was able to catch on with no problem. This book is helping her to expand her knowledge and branch out to more complex techniques. Right now, she is trying to learn about increases, decreases and binding off.
I like that they had extra knitting type crafts, like making pom-poms (one of our favorites!). My daughter is hoping to make easy handmade washcloths from Creative Kids Complete Photo Guide to Knitting for her siblings for Christmas.
Creative Kids Complete Photo Guide to Crochet is a colorful land fun book filled with clear photos and details for kids to learn to crochet. My daughter started out with the simple braided friendship bracelet was something she could easily handle.
I like how Creative Kids Complete Photo Guide to Crochet shows and explains a new technique and then follows that up with a craft that uses the newly learned skill, so you can see it in action. It also works well with trying to gradually attempt harder skills so you have a good foundation for them before you try them out.