No personal judgment against a defendant is valid unless the court which renders it has first obtained jurisdiction over the person of such defendant. This is elementary and fundamental, and goes to the essence of the judgment. And such jurisdiction must be secured through the actual service of process upon the defendant against whom the judgment is sought or through his voluntary appearance in the action.
Sunderland, Edson R. "Preserving a Special Appearance." Mich. L. Rev. 9 (1911): 396-411.