This book is an attempt to reconstruct the foundations of Indian philosophy which are reflected in early Indian texts dated between 13th and 6th B.C.E. They are religious texts composed in Sanskrit which were transmitted orally in the families of priests called Brahmins.
They constitute the intellectual foundation of Indian culture called Śruti (śruti), literally, 'what has been heard'. The earliest layer is the four Vedas: the Veda of ?k-stanzas (?gveda, ?V), the Veda of Saman-chants (Samaveda, SV), the Veda of Yajus-formulas (Yajurveda, YV) and the Veda of Atharvans (Atharvaveda, AV).
The second part of the title refers to a further aim of the book, which is to present a history of ancient Indian thought.