Why We Fight (1942-1945/2000)

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

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 has been released on several labels, two of which are listed below.

Purchase the Periscope Film Blu-ray Disc set from Amazon
Purchase the Periscope Film Blu-ray Disc set from Periscope Film
Purchase the Alpha Video DVD set from Amazon
Purchase the Alpha Video DVD set from oldies.com