The note on the top of the letter is signed by "Dorothy" and the letterhead includes name of Dorothy Jones as Administrative Assistant to M. R. Zigler in Geneva Switzerland.  Since the Dorothy in the letter departs from ... and returns to ... Geneva, I am thinking that these are the same people.

I am assuming that Dorothy is a member of the Church of the Brethren since she is working for the Brethren Service Commission.

Dorothy also addresses the note to Mrs. Schutz.  It the spelling is correct and I was able to read the handwriting correctly, this might be the wife of J. R. Schutz, professor at Manchester College who died in 1945.  Following his death, Mrs. Schutz served as Alumni Diretor at Manchester College for 15 years.  I could not find evidence that Dorothy Jones was an alumna of Manchester College, however.

M. R. Zieler was the Director the the Brethren Service Commission, European Program in Geneva Switzerland.

The trip began in Geneva, Switzerlandand went through Frankfurt, Bonn (seat of the German government following WWII), Cologne, where there was evidence of strafing and bombing, Belgium, Holland, Delft, the Netherlands, the Mennonite Center, Denmark, Bremen, Kassel House, the home of Joe and Helen Dell (Helen Metzler Dell)  -  (Joe was working with the heifer program) ....and back to Geneva.  It is an interesting documentary of culture, food, place and custom.