What is the nationality of the person who researched "Underground"?
Julian Assange Julian Paul Assange ( ; born Julian Paul Hawkins, 3 July 1971) is an Australian computer programmer and the founder of WikiLeaks, an organisation which he founded in 2006. He has won accolades including the Sam Adams Award and Martha Gellhorn Prize for Journalism.
Janusz Piekałkiewicz Janusz Piekałkiewicz (1925 in Warsaw – March 9, 1988) was a Polish underground soldier, historian, writer, as well as a television and cinema director and producer. He was a world-renowned author on many aspects of World War II history; over 30 of his books have been printed, most of them in German, and later translated to other languages. He also wrote from his experiences during the war and specialized in detailing operations within the secret services. A unique characteristic of many of his books is that chapters contain two parts. Firstly, he describes details and contemporary quoted sources and then, in the second part, he provides analysis and his own commentaries to those events. According to critics, this results in a very objective presentation of the material. In addition to his well-known history books, he also wrote books about treasure hunting.