The number is the ISBN-10 for the book American Sphinx: The Character of Thomas Jefferson by Joseph J. Ellis. A file named 0679764410.rar likely contains a digital copy (such as an E-book or audiobook) of this National Book Award-winning biography. Guide to Accessing American Sphinx

: Available at major retailers like Amazon or Barnes & Noble.

: You can often find affordable physical copies on eBay or Better World Books . Warning on .rar Files

: If the archive contains a .pdf , .epub , or .mobi file, use trusted software like Adobe Acrobat or Calibre to view it.