Kenneth Bressett 
The Official American Numismatic Assiciation Grading Standards for United States Coins [EPUB ebook] 

This comprehensive and easy-to-use guide provides the official American Numismatic Association grading standards for every United States coin minted since 1793. Beginners, advanced collectors, and dealers will all find the text understandable and invaluable for grading coins, both circulation strikes and Proofs. Every standard grade is illustrated and described in detail. Every coin is studied, from half cents to gold double eagles, plus comemoratives. Text descriptions of 30 levels help you pinpoint grades from Poor to Mint State. Detailed photographs show you exactly what to look for. All 11 levels of Mint State are discussed in detail.