A vintage illustration of the stacks built below the New York Public Library's reading room.

Depths of the “stacks” at the NY Public Library from about 1910. Notice the dumbwaiters for the books and the pneumatic tube system which is still used to move papers around. The books were or are apparently ordered by size in the stacks. The stacks were closed off to the public in the 1950s because people were living down there. 

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