Book of Signals

When I was in my late twenties, Mama Lai was distraught that her eldest daughter did not have a serious boyfriend:

"Are you giving the right signals?  You can be very cold.  Boys need encouragement.  You have to give them hints to encourage them."

I asked Mama Lai what signals she was talking about.  Mama Lai looked at me with exasperation:

"I don't know!  You like to read books.  They make books about everything.  There must be a book about signals and then you should read it."