This work summarises Indias intellectual history, which in its various aspects has been the subject of my studies for slightly more than half a century. It sets forth the mental development of the most easterly branch of Aryan civilization since it entered India by land, till it came in contact by sea with the most westerly branch of the same civilization after a separation of at least 3000 years. The range of our knowledge of Indias past is so extensive that the information supplied by this book could only cover the main and essential points. Its contents are meant, within a small compass, to direct the reader through the long tract of time from the beginning of the Vedic age down to the epoch when the modern European became acquainted with the Indo-Aryan. All this will contribute something to clearer mutual understanding by our two civilizations.