It is required that all parties with a legal interest in the subject matter of the litigation be joined as parties. Alvino v. Alvino, 659 S.W.2d 266, 269 (Mo. Ct. App. 1983). This is true even if there are no claims of wrongdoing directed at a party. By way of example, if there is a lawsuit questioning the ownership of a bank account, all interested parties in the account should be joined as parties so that they have an opportunity to be heard; as a further example, in suits relating to the construction and interpretation of a contract, usually all parties to a contract must be joined.
Courts will generally not entertain suits unless all necessary parties are before the Court. Under Rule 52.06, Missouri courts have the power to, on their own motion, join a necessary party. Additionally, the appellate court may even raise the issue of failure to join a necessary on appeal after a case has been tried at the trial court level. Contact with questions.