The IRS conducts three types of audits: (1) correspondence; (2) office; and (3) field audits. Correspondence audits are usually for less serious matters and are considered routine. The audit is generally conducted through the mail and by fax. However, even a correspondence audit may be expanded as the investigation unfolds. Office audits involve meeting with an IRS revenue agent (the auditor) at an IRS office. They typically often involve questions about deductions or expenses. Finally, field audits are reserved for the most complex cases and may take place at the location of a business under audit. While some audit issues are relatively simple and can be resolved by the taxpayer, other audits (particularly office and field audits) should be handled with the help of a tax lawyer to protect your interests.