An exception to the res judicata principle that judgments are final, the collateral order doctrine allows for review of a narrow category of court orders. The collateral order doctrine emerged in Cohen v. Beneficial Industrial Loan Corp., 337 U.S. 541, 546-47 (1949). In that case the Supreme Court held to be appealable those orders which “finally determine claims of right separable from, and collateral to, rights asserted in the action, too important to be denied review and too independent of the cause itself to require that appellate consideration be deferred until the whole case is adjudicated.”