I do not recommend this book as it has bias opinion on particular community people. U may feel it while u reading it. I think in between he showed his personal opinion. For upsc preparation choose some other sources. Bcz it do not give us clarify info. In many areas without proofs he argued that our people learned scientific matters from foreigners. Simply he complaint over particular community people for everything. This shows us his opinion. That's y our Indian Govt removed his portions from NCERT.