This volume provides a detailed resume of current knowledge about the classical Indian philosophical systems of Nyaya and Vaisesika in their earlier stages, i.e. covering the literature from their inception in the sutras of Gautama and Kanada up to the time of Gangesa (about A.D. 1350). This dividing point is regularly accepted in the tradition, since with Gangesa it is felt that a new start is made within the systems, the result coming to be known as Navyanyaya, “new” Nyaya. The summaries are arranged in this volume in relative chronological order to assist the reader in tracing the development of the syncretic school’s thought. Scholars around the world – India, Japan, America – have collaborated in the undertaking. The summaries in the volume serve as a tool for introducing Indian thought into their courses on problems of philosophy, history of thought, etc. and guide the students for further study. The index appended will enable the reader to identify all the passages summarized here on a particular topic. The competence of the authors of summaries include the Indian collaborators’ knowledge in depth of Indian thought and the Western points of view of the Western scholars.