India has "philosophy" in the Western sense of the term, and it began early. This book deals with the roots of that philosophical thought. Included here are plain English translations (with notes) of selections of the Rig Veda, Atharva Veda, and especially the classic Upanishads. Also included are five essays to help understand this philosophical reflections. These essays are on the sources of Indian philosophy, knowledge, metaphysics, and ethics, with a specialized essay on "unknowing" in the Isha Upanishad.