- Hitler's Secret Book: The Life and Work of Adolf Hitler's Secret Agent in the United States and South America (1993): A non-fiction book about Nazi Germany's secret intelligence operations in the Americas during World War II.
- The Gold Train: The Destruction of the Third Reich's Gold Reserves (2002): A non-fiction account of the fate of the Nazi regime's gold reserves during the final days of World War II.
- Albert Speer: The End of a Myth (2008): A biography of Albert Speer, the Nazi Minister of Armaments and War Production, exploring his role in the Nazi regime and his controversial post-war life.
- Terror on the Airwaves: The Nazi Radio Propaganda Offensive against the United States, 1941-1945 (2010): A non-fiction book examining Nazi Germany's propaganda efforts targeting the United States through radio broadcasts during World War II.
- The Rise and Fall of the Waffen-SS: Hitler's Elite Guard at War, 1940-1945 (2011): A military history of the Waffen-SS, an elite combat formation of the Nazi SS, from its formation to its defeat in World War II.
In addition to books, Garvens has written numerous articles, essays, and reviews for publications, including The New York Times, The Wall Street Journal, Der Spiegel, and The Independent. He is a frequent contributor to historical documentaries and has appeared as an expert on various television programs.