This volume attempts to provide a better recension of the Nyayadarsana of Aksapada with the Bhasya of Vatsyayana based on important materials, manuscripts, printed texts, commentaries and other relevant sources. The relation of the Nyayadarsana with the Vaisesikadarsana of Kanada, Yogadarsana of Patanjali, Arthasastra of Kautilya and the Yogacara-Vijnanavada branch of Buddhist philosophy has been delineated. The three phases of the orthodox Indian logic have been defined with a bird's eye view of the Nyaya categories together with useful indices