Question

Why was the book written by one of Helen's ancestors a singular coincidence

Answer 1

The book was written by one of her Zurich ancestor about the education of dead and blind.little did he know that one of her own descendents would suffer from a similar handicap later on in life
This she refers to it as a singular coincidence

Answer 2

Answer :

In her book 'The Story Of My Life,' Helen Keller says “One of my Swiss ancestors was the first teacher of the deaf in Zurich and wrote a book on the subject of their education-rather a singular coincidence; though it is true that there is no king who has not had a slave among his ancestors, and no slave who has not had a king among his.”

The book on the subject of education of deaf children, written by one of Helen's Swiss ancestors is a singular coincidence as the ancestor did not know that he would have a deaf and blind child in his family lineage one day. Helen refers to it as an unmistakable, singular coincidence.