Hello Ashish,

    I understand your concern and I am here to help you regarding your and i appreciate your interest towards UPSC.

   Generally, there are many books in the market for UPSC preparation and some of them are on the too list and i mention them below as follows,

• Indian polity for civil services by M.Laxmikanth
• Indian art and culture by Nitin Singhania
• Oxford atlas
• Indian economy hy Ramesh Singh
• Economic survey by ministry of finance
• India year book (Current affairs)
• NCERT books.

So, these are some of the books which are very important in the UPSC examination point of view. You can also go for extra books also to grab more marks.

Hope this helps !!

All the best !!