Each state has its own system of taxation. These may include business or corporate income taxes, sales taxes, excise taxes, personal income taxes and property taxes. Some have special taxes such as a yield tax or a severance tax. Other states such as Alaska, Florida and Wyoming, to name a few, do not have an individual income tax. New Hampshire is one of the states that does not have a local sales tax. Alaska also has no sales tax but some of its local cities and regions do. Whatever taxes a state may have to pay leaves you open to a state tax audit. An audit is often referred to as "checking the books." It is a thorough investigation of the actual books of account, computer documents and supporting evidence. In this process, the state auditor examines the legal entries and compares them to what has been submitted in an attempt to prove or disprove the accuracy and reliability of the information provided or filed. A state tax audit is a tool of the state tax authorities to ensure a business or individual does the best to keep "the books" honest.