When an encrypted letter written by Thomas Jefferson is found hidden in the attic of an old farmhouse in Virginia, the information could offer a clue as to who killed a U.S. Special Forces soldier 220 years after the letter was written. Paul Marcus, who five years earlier, broke an coded paper written by Isaac Newton, is asked to see of he can unlock the secret Jefferson had originally meant for one person in 1804. More the two centuries later, the...