LAS VEGAS -- A federal judge ordered a man who claims that tax paying is voluntary in the United States to stop selling his book and giving seminars.

Irwin Schiff is the author of "The Federal Mafia: How It Illegally Imposes and Unlawfully Collects Income Taxes," and offers paid seminars on the topic. Schiff said the judge's temporary order violates his First Amendment rights.

"Banning a book! The government is trying to prevent me from telling the truth about the income tax," the 75-year-old said Thursday.

Department of Justice lawyer Evan Davis said Schiff advised people to file false income tax returns listing zero income and zero liability, and had 3,100 clients attempting to evade $56 million in taxes. Davis called it one of the largest tax scams in U.S. history.

The judge issued the temporary order against Schiff on Wednesday and will decide April 7 whether to make it permanent.