NIOS History Books For Competitive Exams- Both In English / Hindi: Understanding Indian History. Understanding Indian History– Hindi.  The Geographical Setting and pre-historic cultures of India.  The Geographical Setting and pre-historic cultures of India– Hindi. The Harappan Civilization. The Harappan Civilization– Hindi. The Vedic Age (1500 BC-600BC). The Vedic Age (1500 BC-600BC)– Hindi. From Janapadas