@King_of_Sexytown
There are many types of auditors but they essentially do the same thing: ensure compliance with performance, standards, rules, other procedures and in some cases, accuracy of financial, corporate, governmental and personal statements.
Public companies are audited by Certified Public Accountants under requirement by the SEC. The purpose of this is not just legal compliance, it is also to protect the ultimate owners of the company, the shareholders.
Banks or other lenders may require audits in order to support credit decisions or to make sure that company performance meets the agree-upon covenants in an existing loan document. A bank can not examine the detail behind a company’s financial statements for all of its creditors. In sum, they ask the auditors to confirm the value of assets and liabilities as of a given date and to confirm that the reports of income and expenses are stated reasonably.
Other types of audits would be audits by tax authorities, OSHA audits (which protect employees), performance audits among others.
I have never been an auditor, working for corporations all of my life and when the auditors visit they can be a real pain, but they are there at the instruction of our Board of Directors and must be viewed as a necessary evil.