Which rule would you refer to for guidance on permissive joiners?

The reference for permissive joinder of parties is found in Rule 20. This rule allows individuals to join together in one action as plaintiffs or be joined together as defendants if they have claims or defenses that arise out of the same transaction or occurrence and there are common questions of law or fact.

The purpose of Rule 20 is to promote judicial efficiency and consistency by allowing multiple parties to be included in one lawsuit when their claims or defenses are related. By facilitating the joining of parties with interconnected issues, the rule aims to reduce the potential for conflicting judgments and to streamline the judicial process, making it more efficient for the court and the parties involved.

In contrast, the other rules mentioned serve different purposes: Rule 19 deals with mandatory joinder of parties, Rule 21 addresses the misjoinder and non-joinder of parties, and Rule 22 pertains to interpleader actions where a party may be unsure of whom to pay or what obligations they have. Understanding the specific focus of each rule is essential for applying them correctly in practice.