Pulp paper .
Yes, In fact this was when the superman comics were first released.
comics wern't made until 1939 and they costed 10 cents
Pluto was discover in the 1930's along with the helicopter.
in the 1930's
1930's.
Warner brothers made this in the 1930's
It was just the way that they were made.
1930's
Sometime in the 1930's
Aluminum
-in the 1930's Albert S. Hyman
Look at the year they where made and the quality of the book