Definition: It is a rule in actions ex contractu that all who have a legal interest in the contract, and no others, must join in action founded on a breach of such contract; whether the parties are too many or too few, it is equally fatal. 8 S. & R. 308: 4 Watts, 456; 1 Breese, 286; 6 Pick. 359. 6 Mass. 460; 2 Conn. 697; 6 Wend. 629; 2 N. & M. 70; 1 Bailey, 13; 5 Verm. 116; 3 J. J. Marsh. 165; 16 John. 34; 19 John. 213; 2 Greenl. 117; 2 Penn. 817.
2. In actions ex contractu all obligors jointly and not severally liable, and no others, must be made defendants. 1 Saund. 153, note 1; 1 Breese, 128; 11 John. 101; J. J. Marsh. 38; 2 John. 213.
3. In actions ex. delicto, when an injury is done to the property of two or more joint owners, they must join in the action. 1 Saund. 291, g; 11 Pick. 269; 12 Pick. 120; 7 Mass. 135; 13 John. 286.
4. When a tort is of such a nature that it may be committed by several, they may all be joined in an action ex delicto, or they may be sued severally. But when the tort cannot be committed jointly, as, for example, slander, two or more persons cannot be sued jointly, although they may have uttered the same words. 6 John. 32. See, generally, 3 Bouv. Inst. n. 2648, et seq.
Legal Dictionary 
