Hello applicant,

*Following are the best books for studying history for UPSC
1. India's Ancient Past by R.S. Sharma
2. The wonder that was India by A.L Basham for Ancient History
3. Medieval India by Satish Chandra
4. Advanced Study in the History of Medieval India all the three volumes by J.L Mehta
5.History of Modern India by Bipan Chandra
6.India's Struggle for Independence: 1857-1947 by Bipan Chandra
7.History of the World by Arjun Dev and Indira Arjun Dev
8. Art and Culture by Nitin Singhania
9. History of Modern India by Ramchandra Guha
10. A History of Ancient and Early Medieval India by Upinder Singh

Hope it helpful