Dear Vihaa,

There are 8 best books for KAS exam according to me-

1 Chanakya kanaja  Kannada exam.

2 KPSC Group C Non - Technical Exam Karnataka 2017 - 18 English Medium

3 KPSC KAS Books For Mains Exams General Studies a Set of 4 Books in Kannada

4 KPSC Group C Non - Tech Exam 2016 - 17 Kannada II Paper

5 KPSC Group C Non - Tech Job Preparation ( Kannada and English )

6 KAS Exam English by KPSC 2017 - 18

7 KPSC Group C Non Tech Exam Karnataka 2017 - 18 in Kannada

8 Mental Ability Kannada Exam

Hope this helps!!