This is a prakaraṇa text on the Nyāya theory of vyāpti written by Jagadīśa. The main theme of the work centres around the nature of vyāpti.Knowledge of vyāpti is the cause of inferential knowledge. If the definition of vyāpti is constructed in terms of avyābhicāritatva, then one could explain avyābhicāritatva in five alternative ways. And none of these alternatives is acceptable, for this understanding of vyāpti would fail to account for kevalānvayi inference. In order to remove this problem, the definition of vyāpti is reconstructed as pratiyogivṛttidharmāvacchinna-pratiyogitākabhāvarupa vyādhikaraṇadharmāvacchinnabhāva. Jagadīśa examines this new definition of vyāpti and offers his justification, refuting all the possible objections.