Fivaz has written over a dozen books focused on numismatics/coin collecting, and is best known as the co-author of The Cherrypickers' Guide to Rare Die Varieties, first published in 1990 and subsequently re-issued seven times.
[4] At the American Numismatic Association's 2003 World's Fair of Money in Baltimore, Fivaz's collection, including Buffalo nickels, Mercury dimes, silver dollars, errors, and counter-stamped coins, was sold at auction.
In November 2020, Fivaz's "World's Worst Type Set", featuring coins graded "Poor-1" and "Fair-2", was auctioned by Stack's Bowers Galleries.
[6] In June 2022, Fivaz was part of a team of five numismatists who re-classified the 1943 over 42 Lincoln cent as an overdate variety, in addition to its previously known doubled die status.
[7] In addition to his numismatic work, Fivaz was a regional sales manager for Nestle out of its Atlanta offices from 1959-1996.