This book provides information on an issue of critical importance to tax administration in this country; the practice of sheltering U.S. earned income in foreign jurisdictions as a means of avoiding U.S. taxation. Each year, the United States loses an estimated $100 billion in tax revenues due to offshore tax abuses. Offshore tax havens today hold trillions of dollars in assets provided by citizens of other countries, including the United States. A related issue is the extent to which financial institutions in tax havens may be facilitating international tax evasion. About 50 tax havens operate in the world today with their twin hallmarks being secrecy and tax avoidance. Billions and billions of dollars worth of U.S. assets find their way into these secrecy tax havens, aided by banks, trust companies, accountants, lawyers, and from offshore tax abuses. This book discusses such sources of tax havens, as well as the steps that the IRS has taken to alleviate this problem.