A federal appeals court has ruled that a well-known tax protester cannot sell his book, "The Federal Mafia," because it encourages people to commit fraud.

Irwin Schiff, 76, of Las Vegas, who authored the book and owns a book store, may be able to sell a new version of the book if he removes the parts that push his tax evasion products and services, the New York Times reported Tuesday. Anyone but Schiff and two of his associates can sell the $38 book, the court ruled.

Schiff has gone to federal prison twice for tax crimes. He was indicted in March for helping more than 3,600 people try to avoid $56 million in taxes by reporting zero income on tax returns. Schiff calls the strategy a legal way to escape taxes, but the courts have rejected that claim, the Times reported.

Under law, the government is allowed to ban commercial speech if it encourages people to commit crimes. The U.S. Court of Appeals in San Francisco contended that the book was a central part of Schiff’s marketing of tax-evasion schemes, therefore making it commercial in nature.

"The defendants have been selling products that help their customers engage in illegal activity," the decision said.

Allen Lichtenstein, an attorney who represented booksellers, publishers, the ACLU and other groups that supported Schiff, said he believes the book can be sold if the false commercial speech is removed and the book contains only "unorthodox tax theories."

Schiff told the Times that demand for his tax advice has not slackened. "I just finished meeting with this elderly couple—the guy has emphysema—who owe no taxes, but the government is trying to make them pay," he said, adding that he kept only half his usual fee in that case.