Disquisitiones Arithmeticae

English translation of standard mathematical work on theory of numbers, first published in Latin in 1801. "Among the greatest mathematical treatises of all fields and periods."--Asger Aaboe. 
Summary: Great Classic Math Book from a Master
This is an incredible work, painstakingly and lovingly translated by someone with more patience than I might ever have. Thank God there are people out there who can do such tedious things so we can all enjoy these great works in English.