"Walter Breen's "Complete Encyclopedia of U.S. and Colonial Coins" changed the landscape of American numismatics. Before this book was published, the most authoritative research appeared in auction catalogs. There, the assertions, however right they might have been, were seldom backed by documentary proof. Walter Breen changed that.

The Breen Encyclopedia brought academic scholarship to American numismatics. Breen footnoted his claims with supporting evidence from primary sources. This is how we learned to write term papers -- and the Breen Encyclopedia is nothing if not a 750-page term paper (with 4000 illustrations).

Breen completed a four year degree in one year at Johns Hopkins University. He was brilliant. His genius shines through this work. He does have his prejudices and quirks. He saw paranoia and conspiracies in other people quite readily. However, his editorial assertions are easy to cull. The Breen Encyclopedia came out in 1988. In the last 12 years, some new facts have surfaced. For instance, we now believe that among the Shield Nickels, Judd 417 and 419 are back-dated fantasies and Breen 2466 may be a mule fantasy. These little amendments cannot detract from the overpowering value in the Breen Encyclopedia, but instead, prove that all numismatists must continually search for truth rather than relying on authority. The publication of the Breen Encyclopedia deserves to be noted among the greatest events in the last 100 years of American numismatics."