Mary Thomas, a CPA and attorney, is principal of Thomas & Thomas, PC. in Houston. She works exclusively in multi-state sales and use tax matters. Prior to joining the family businesses, Mary worked as a compliance auditor at an internationally known health institution and as an auditor at a Big Four accounting firm. Mary and her sister, Stephanie, started The Sales Tax Sisters, a practice solely devoted to educating accountants, bookkeepers, small business owners (DIYers), and novices on basic information about sales and use tax. Find Mary on Twitter @TaxSisters.