What is attorney/client privilege?

When someone retains an attorney, they need to be able to discuss their legal concerns freely with an attorney, so that the attorney can accurately assess their situation and give the best legal advice. Also, if a plaintiff’s attorney was privy to all discussion between a defendant and his attorney (and vice-versa) they would have a hugely unfair advantage during trial. In light of this, the courts respect a certain type of confidentiality between the attorney and his client, which is called attorney/client privilege. This means that discussions between the attorney and his client can’t be involuntarily disclosed in court (by testimony, subpoena, discovery, deposition, or any other means) or during any investigation, regardless of whether the proceeding is civil or criminal in nature. Of course, the client (though not his or her attorney) could volunteer such information if s/he wanted to. It should be noted that only attorneys have this privilege; CPAs do not have attorney/client privilege between them and their clients.

See also Privileged Work Product