Taxay's first published work was Counterfeit, Mis-Struck and unofficial U.S. Coins, in 1963, followed by The U.S. Mint and Coinage in 1966 (which Gilroy Roberts called "the most complete and authoritative treatise on the subject ever written"), An Illustrated History of U.S. Commemorative Coinage in 1967, Money of the American Indians in 1970, and Scott's Comprehensive Catalogue and Encyclopedia of United States Coins in 1971. He also served as the curator of the Chase Manhattan Bank's Money Museum.
In 1974, he joined award-winning numismatist Harry Forman in establishing the coin dealership of Forman, Taxay and Associates. In approximately 1977, Taxay withdrew from society.
In 2005-2006, the members of the Numismatic Bibliomania Society's mailing list undertook a joint research project to discover what had happened to Taxay. They established that Taxay had been introduced to Indian spirituality by Walter Breen, and that as a result, Taxay became a Rajneeshee and emigrated to India. Historian Karl Moulton—whose 2007 Henry Voigt and Others Involved in America's Early Coinage includes a chapter analyzing Taxay's historiography—speculates that Taxay attempted to liquidate all his property so that he could donate his wealth to the Bhagwan Shree Rajneesh, and describes him as "brainwashed and untraceable", concluding that Taxay's ultimate fate may never be known.
- Joe Planas (July 20, 1969). "1792 Billion Cent Controversial". Lincoln Sunday Journal and Star (via Newspapers.com). p. 12. Retrieved July 12, 2015.
- THE U.S. MINT AND COINAGE, By Don Taxay, at Kirkus Reviews, retrieved April 11, 2012
- ANA NAMES HARRY FORMAN 2000 NUMISMATIST OF THE YEAR; August 12, 2000; by the American Numismatic Association, at money.org (via archive.org); retrieved April 11, 2011
- WHATEVER BECAME OF DON TAXAY?, from The E-Sylum newsletter - Volume 8, Number 54, December 25, 2005, Article 10, by Wayne Homren; archived at coinbooks.org; retrieved April 11, 2012
- DON TAXAY WHERE ARE YOU?, from The E-Sylum newsletter - Volume 9, Number 1, January 1, 2006, Article 9 , by Wayne Homren; archived at coinbooks.org; retrieved April 11, 2012