Four adults traveling to Salzburg and Cienna in late May, we are looking for suggestion of a private guided tour in each city.
Here is the official list of authorized/certified tour guides for Vienna:
For Vienna, I and another forum member recommend Gerhard Strassgschwandtner. So does Rick Steves in his Vienna/Salzburg guide book. Gerhard is genial, knowledgeable, and enthusiastic. He also is the owner/curator of the Third Man Museum in Vienna. His website for tours: http://www.special-vienna.com/
I am a private guide kind of guy, but I've never felt a need for one in Salzburg. RS has a great walking tour of the Altstadt (Old Town) in the Vienna/Salzburg guide. He also has a few recommendations for private guides in Salzburg.