No one in our society has a more compelling need to communicate in complete confidence with a lawyer than a prisoner, when challenging a conviction as wrongful or prison conditions as unlawful. No one has a greater need to be able to engage in the uninhibited discussion of highly personal matters, tragic events, and official misconduct. A prisoner’s constitutional rights to freedom of speech, access to the courts, due process, and assistance of counsel are placed in unique jeopardy when a correctional system insists on prying into the substantive contents of legal mail. In this Article, we explain the vital need for confidentiality in prisoner correspondence with legal counsel to avoid chilling prisoner expression and allow lawyers to ethically and effectively represent prisoners; survey the written policies of the nation’s correctional systems regarding legal mail; describe and analyze the constitutional protections for prisoners in confidential correspondence with lawyers through the rights of free speech, due process, access to the courts, and assistance of counsel; and address the procedural steps and obstacles for a prisoner to seek relief from the courts when that confidentiality is breached by prison policies or practices.