Info at
http://en.wikipedia.org/wiki/Sher_Shah_SuriObverse
Kalima-e-tayyabah (
lā ilāha illā-llāh muhammadan rasūlu-llāh; there is no god but Allah, and Muhammad is his prophet), enclosed in a square
The margins should have the names of the four successors: Abu Bakr below, Umar at the left, Uthman above, Ali at the right.
Reverse
Inside square (top):
es-sultan Sher Shah khallad Allah mulkahu (the Sultan Sher Shah, may Allah perpetuate his kingdom)
Inside square (bottom):

Devanagari legend "Sri Sersahi" (often very faulty, as on this coin)
The margins should have
farid ed-dunya wa as-din abu al-muzaffar zarb Gwalior (Unique one of the world and of the faith, father of the vioctorious, minting of Gwalior.)
Mint mark of Gwalior
Year: 951 AH (1544 AD)

PS: Sher Shah was the one who introduced the
Rūpaya (Rupee).