The key distinction between misjoinder and non-joinder of parties lies in the inclusion or exclusion of parties in a case. Misjoinder occurs when parties are improperly joined in a lawsuit—meaning parties are included who do not belong together due to unrelated claims or defenses. Non-joinder, on the other hand, happens when an essential party is left out of the case, meaning a party who should have been included to properly resolve the issues is omitted. Misunderstanding this difference can significantly impact the outcome of a case. In the case of misjoinder, improperly joined parties might be removed or the case could be severed, potentially delaying proceedings. In the case of non-joinder, the case may be dismissed or the absent party could be added later, potentially causing complications in terms of jurisdiction or case management. Therefore, understanding and addressing both issues early is crucial to avoiding delays, ensuring a fair trial, and preventing the need for additional motions or dismissals.