A must read — available online. It tells you what the civilisation was and how it was transmitted to the west from India through Arabia.
Origins of Vedic Civilisation by Kenneth Chandler, Ph.D.
The Indus-Saraswati Valley Civilizations spread over more than 250,000 square miles, and included over 1600 sites. Most of the villages and cities were laid out on an exact north-south grid on sites west of the river, and were built with kiln-fired brick of uniform size. Sites have been found dating from 6,500-7,000 BC.
The Vedic civilization, far more ancient than the Greek, spread from India to Europe, via Anatolia, Thrace, and Greece, and from there into Western Europe. The direction of the flow was from India into Arabia and then to Europe. Evidence shows that the Vedic tradition entered into Europe sometime before the early fourteenth century BC.
The Rig Vedic tradition and its literature almost certainly came into existence sometime long before the earliest civilizations of Mesopotamia, Sumeria, and Egypt. These were relatively late events in the history of civilization and probably owe their existence to the earlier civilization of Vedic India.