Defendant challenged plaintiff's right to foreclose, arguing N.J.S.A. 12A:3-309 precluded the enforcement of a note, lost prior to the assignment of a concomitant mortgage, because plaintiff never owned or controlled the underlying debt. The court interpreted the statute as allowing the enforcement of a lost note where the assignor – which provided a lost-note affidavit to plaintiff – possessed the note and was entitled to enforce it when the loss occurred, and plaintiff proved the terms of the note and its right to enforce it.