Peter Hendrickson is a convicted felon and domestic terrorist who has been a long time promoter of various tax protester schemes. He is most famous for his book Cracking the Code, which claims to prove that the income tax only applies to people who are employed by foreign corporations or the federal government. Hendrickson also gives a step-by-step method for falsifying amended tax returns to get post-hoc tax rebates from previous years of income tax payment. He runs a website and online forum called Lost Horizons where various victims, criminals and marks who have fallen for Hendrickson's scam post their rebate checks, and then discuss how to avoid jail time and massive fines after the IRS busts them for fraud and conspiracy.
Every single one of Hendrickson's arguments has been rejected by the courts and people who follow his methods are lucky if they only wind up losing everything they own, while others wind up spending years in jail.
On April 16th 1990, Hendrickson conspired with several individuals, including his then girlfriend (now wife), to place a fire bomb in the mail. This was planed to coincide with the due date for yearly income tax returns. The bomb exploded and injured a postal worker as well as a bystander. Hendrickson plead guilty to one count of willful failure to file an income tax return as well as conspiracy to place an incendiary device in the United States mail. He served 21 months, getting off easy by his willingness to turn state evidence against his fellow conspirators. 
On November 12th, 2008, Hendrickson was indicted on 10 counts of filing false documents with the Internal Revenue Service. According to the indictment, Hendrickson filed false income tax returns (Forms 1040) and false substitutes for wage statements (Forms 4852) for the years 2000, 2002, 2003, 2004, 2005, and 2006 reporting that he had received no wages in those years even though he had in fact received wages in those years.