He presented his currency to merchants as payment for goods and services. If the bills were accepted, he asked for a receipt and, when appropriate, change. He noted the details of each transaction on the backs of his “Boggs bills,” which were blank, and sold the receipts to collectors. It was up to them to track down the merchant — for a fee, Mr. Boggs would assist — and negotiate purchase of the note.

Mr. Boggs never sold his bills. He only spent them.

The assembled elements were, in the opinion of Mr. Boggs and his admirers, artworks, exhibited as such in galleries around the world and included in the collections of the Art Institute of Chicago, the Museum of Modern Art in New York and the Smithsonian American Art Museum in Washington.

“I create images that say things and ask things,” Mr. Boggs said in the 2013 Discovery Channel documentary “Secret Life of Money.” “I take them out into the real world and try to spend them, not as counterfeits, but as works of art that ask us about the nature of money.”

Law enforcement agencies in several countries took a different view. They regarded Mr. Boggs as a forger. They expressed this opinion, on several occasions, by seizing the notes or putting Mr. Boggs on trial.

“They said I was a counterfeiter,” an indignant Mr. Boggs told The Associated Press in 1992, when agents in the counterfeiting division of the Secret Service raided his apartment near Carnegie Mellon University in Pittsburgh, where he was an artist in residence, and took possession of more than 100 of his artworks. “They don’t understand the difference between art and crime.”