These copper plates are from the Indus Valley civilisation, also known as the Harappan civilisation. As the study indicates:
The settled life in the Indian subcontinent started, as is evident at Mehrgarh in Baluchistan ( Jarrige, et al., 1995 ), around 7000 BC and there has been gradual growth in the cultures culminating into the formation of the Harappan culture starting around 4000 BC.
We don't know a lot about these people, as the script they used has not been deciphered. But they were an inventive people, as would be further demonstrated if the claim can be further demonstrated to be true, that these plates were the first (that we know of) attempts to reproduce information by block printing
Here's an image of some of the copper plates:
A close up of one plate
and a sample of printing with one of the plates:
Check it out at: http://www.ancient-asia-journal.com/article/view/aa.12317/97.
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This is far earlier than the earliest printed book that we know of, as illustrated here:
which is Jikji's , "Selected Teachings of Buddhist Sages and Son Masters" from Korea, the earliest known book printed with movable metal type, circa 1377. (from Bibliothèque Nationale de France , Paris)