I don't have a clue what she's getting at. But she definitely wasn't a fan of the sort of action we go for these days. I imagine she means something other than 'string height'' by 'action' and why worry about 'true pitch' if you have an adjustable bridge?
It's a very odd book, typical of the sort that would have terrified me by its reliance on musical notation, but it obviously got a lot of folks started.
I think the book was partly aimed at upright players 'converting' to electric:
There is some good advice: