Lotte Lehmann was a legend in her own time. She was a famous Marschallin and was considered the greatest interpreter of Fidelio. She was also a prominent recitalist.
She wrote a series of books intending to teach singers how to properly present Lieder. Each song was laid out in a specific choreography. Put your hand up here. Look down here. I think this is a good idea in general because it would prod singers to actually think about how they want to present a piece. They could go on to make up their own choreography, one closer to the feeling of their own hearts. She retired to one of the great teaching gigs at the University of California at Santa Barbara.
The problem with her advice is clear when listening to "The RCA Victor vocal series: Lotte Lehmann." Her French is fine. She sings some of the same Reynaldo Hahn songs that are on Susan Graham's recording and presents them in a much more passionate style. This woman, once famous as an interpreter, seems too old-fashioned to us. Her use of the tools of interpretation is too broad. We want a lighter touch.
Singing, like all of art, is of a time and a place. She is now a person from the past.