When you consult with a licensed attorney, everything you tell them, including notes in their files, and in most situations the tax research and their advice and recommendations to you is privileged and private. The attorney cannot be forced to reveal any of those items if subpoenaed or questioned by the IRS or in a legal matter.
You need to keep this Attorney-client privilege in mind when consulting a tax professional concerning entering any of the IRS Voluntary Disclosure Programs and seeking counsel on past unfiled tax returns or tax problems (both civil and criminal). Discussing the situation with anyone other than an attorney could later be used against you.
It is often best when their are potential tax problems or possible criminal consequences to have an Attorney actually hire the accountant to prepare any required returns in order to keep as much as information as legally possible from being subject to discovery. Documents that are connected with the actual preparation or information which is on your tax return (or information which should be on your return) cannot be kept confidential.