An honest suggestion to aspirants! Please do not buy any book authored by any tom dick and harry. Internet is the best source for preparation. You can find 1000+ websites on every single subject, available free of cast in written as well as video lectures. Please spend time on research and them make your own notes. If you can't find any recommended book, at least don't waste your hard earned money to buy local books.
Some of the useful links for US History as an example:
US History:
1:
https://www.ducksters.com/
2: Yale University Video Lectures on History of USA :
https://www.youtube.com/watch?v=shTB...EBE077F9257558
3.
https://www.youtube.com/watch?v=Fp6m...VCZERhhy9CC1S6
4.
https://www.youtube.com/watch?v=67V1...YlOol1AEz0Aayo
5.
http://www.ushistory.org/