Vienna was a city located in Austria, Europe.
In Dangerous Ground, Doctor John Rawley spent some of his four years after graduating from Johns Hopkins in this city. During his stay in Vienna, Dr. Rawley studied psychiatry. (TNG: "The Big Goodbye")
The pages seen in the episode were from the mystery novel,
Dangerous Ground, by author Frances Sil Wickware. This novel was published in 1946. Information on Vienna was from page 12.