Elisabeth Haich was a yoga teacher. In this book she talks about a series of past lives and an initiation ritual that she participated in in ancient egypt. An excellent read.
I have seen some egyptian paintings and illustrations that depict figures who appear to be doing yoga asanas. Much has been said also about how the word asana means "seat" and some connections to the goddess Isis who was often symbolized as a chair, and also to 2nd chakra stuff. The 2nd chakra being the "seat" of the goddess or the feminine.
Most certainly it is relevant. Looks like a good book.
I would really recommend Initiation. I have recommended to others before who were interested in symbolism...they loved it.