Synopsis Nyayarahasya is a commentary by Ramabhadra Sarvabhauma on Chapters I-IV of Nyayasutra-s of Gautama, while Anviksikitattvavivarana is a commentary by Janakinatha Cudamani, the father of Ramabhadra Sarvabhauma on Chapter V of Nyayasutra-s. These important commentaries are being published for the first time in the Bibliotheca Indica Series. The present publication is in two volumes. The first volume comprises the Introduction and the text of Nyayarahasya by Ramabhadra Sarvabhauma on Nyayasutras Chapter I-IV. The second volume would contain the text of Anviksikitattvavivarana of Janakinatha Cudamani on Nyayasutras, Chapter V with textual notes and appendices.