American State Quarters: The DEFINITIVE GUIDEBOOK to COLLECTING STATE QUARTERS, by David L. Ganz, is a must read for any numismatist interested in collecting State quarters casually as a circulated set or as an investment as a set registry set. A driving force in the founding of circulating commemoratives, David Ganz gives a unique view at the history, founding, and legislation of State Quarters. This part of the book is very dense, but gives a lot of interesting background as Ganz served on the CACC. David Ganz then gives an excellent five-page overview of the mintage process and a brief history of coins. He moves to the collecting and investing part of State Quarters, how grading affects the value and mint errors. The next part of the book is on the individual coins, where he spends about three pages per state discussing the state, its design, designers, design history and mintage. The second section of the quarter listings is outdated on the copy I picked up from my local library, as it was copyrighted 2008 (the second edition), but David Ganz goes through the price records, error values, and finally a very useful guide on grading one of the 50 issues. He concludes each listing with an investment potential, what grade it is considered an investment, and the potential of circulation finds. Because it is outdated, some of the price guide is dramatically off, but it can still be used as a general marker on what year's errors are especially valuable. Overall this book is a must-read on 50 State Quarters, and a 4 out of 5 star book.