“In the tax profession, there are only three total official credentials. One is the enrolled agent credential. The EA is the only authorized tax practitioner who has technical expertise in the field of taxation and who is empowered by the U.S. Department of the Treasury.” MoneyFinanceIrsJeffrey SchneiderEnrolled AgentDepartment Of TreasureTax Practioner Book:Now What? I Got a Tax Notice from the IRS. Help!: Defining and deconstructing the scary and confusing letters that land in your mailbox. Source: Now What? I Got a Tax Notice from the IRS. Help!: Defining and deconstructing the scary and confusing letters that land in your mailbox.