A lawyer's letter refers to a professional legal document produced and issued by a lawyer who accepts the entrustment of a client, discloses and evaluates relevant facts or legal issues, and then makes a request to achieve a certain effect. The purpose of legal evaluation and risk assessment of a fact with a lawyer's letter is to inform the recipient of the legal facts with the legal scale and the lawyer's judgment, so that the recipient can get his own "legal evaluation", that is, "to convey the meaning of the law".
The essence of lawyer's letter is a legal act of entrusting an agent to express his will, which plays an important role in safeguarding the legitimate rights and interests of the parties. However, the lawyer's letter is not really effective and needs the approval of the court. If the court does not recognize it, it is invalid.