Tax law encompasses the process whereby governments impose charges (or assessments) on individuals, corporate entities, or property, to finance government expenditures on public purposes. These government charges can be imposed on earnings, transactions (e.g., sales), the value of property, on business licenses used to generate revenue, and the like. Tax law spans a web of federal, state and local schemes. Examples include: federal and state Income taxes levied on income earnings, typically tied to the earner's income bracket; real property taxes levied by counties and/or municipalities on the value of the property; local sales tax imposed on a proportion of a business' retail transactions; federal duties levied on imports from overseas, taxes on estates of the deceased, as well as assessments on particular ‘large gifts’ or transfers. Tax law varies by jurisdiction.

• Internal Revenue Service, U.S. Dept of Treasury
  Website for the IRS
• IRS Tax Information for Individuals
  Employees, international taxpayers, military, self-employed, more.
• IRS Tax Information for Businesses
  Corporations, international businesses, small businesses, more.
• IRS Tax Information for Charities & Non-Profits
  Charitable organizations, churches, contributors, private foundations, more.
• IRS Tax Information for Retirement Plans Community
  Benefits practitioner, plan participant/employee, plan sponsor/employer.
• IRS Tax Information for International Taxpayers
  Corporations, international businesses, partnerships, small businesses.

• Canada Revenue Agency (CRA)
  Tax laws for federal government & most provinces & territories.
• U.K. Tax Portal
  Starting point for questions on tax matters in the U.K.
• HM Revenue & Customs (HMRC)
  U.K. dept responsible for collecting direct & indirect taxes.

• I’m facing an IRS tax audit. Should I consult a tax attorney?
  

  Receiving a tax audit notice from the Internal Revenue Service can be a frightening and confusing experience. Most individuals facing an audit may not know how to respond or what is at stake for them personally and financially. Being knowledgeable and prepared is the best way to get through an audit without suffering t..