Tax evasion by individuals with unreported offshore financial accounts was estimated by one IRS commissioner to be several tens of billions of dollars, but no precise figure exists. By law, U.S. citizens are required to report worldwide income from all sources, including income from offshore accounts. While taxpayers can hold offshore accounts for a number of legitimate reasons, some use them to illegally reduce their tax liabilities, often by not reporting the income earned on these accounts. The IRS has operated four offshore programs since 2003 that offered incentives for taxpayers to disclose their offshore accounts and pay delinquent taxes, interest and penalties. This book examines the nature of the noncompliance of the 2009 Offshore Voluntary Disclosure Program (OVDP) participants; the extent the IRS used the 2009 ODVP to prevent noncompliance; and assesses the IRS's efforts to detect taxpayers trying to circumvent taxes, interests, and penalties that would otherwise be owed.