Here is a great link on Buttonholers.
http://en.wikipedia.org/wiki/Buttonholer
I said in my OP that it didn't have the booklet but it did! It was stuck in the top. I was looking through the little booklet that came with my new Magic Key and I found the original receipt folded up on the last page. It was purchased on May 9th 1949 from the White Sewing Machine Center in Long Beach, Ca. and it still looks like brand new! I love provenance, here is the receipt: