Directed by Frank Capra and Anatole Litvak
IMDb (Prelude to War)
IMDb (The Nazis Strike)
IMDb (Divide and Conquer)
IMDb (The Battle of Britain)
IMDb (The Battle of Russia)
IMDb (The Battle of China)
IMDb (War Comes to America)
Wikipedia
Chicago Reader
Letterboxd
Two of the seven entries of this series were released on the Olive Films collection Mr. Capra Goes To War: Frank Capra’s World War II Documentaries (which also includes the Film Registry title The Negro Soldier [1944/2011]):
Purchase the DVD from Amazon
Purchase the Blu-ray Disc from Amazon
The complete series was released on Blu-ray Disc on the now defunct Periscope Film label and is fetching high prices on Amazon.
Purchase the Alpha Video DVD set from Amazon
Purchase the Alpha Video DVD set from oldies.com
Why We Fight is or was available in various other editions and/or collections.